diff --git a/02-variables.html b/02-variables.html
index 51cd3b212..5dfc8cc6e 100644
--- a/02-variables.html
+++ b/02-variables.html
@@ -679,7 +679,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -724,7 +724,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb20">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -764,7 +764,7 @@ <h3 class="callout-title">Challenge<a class="anchor" aria-label="anchor" href="#
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>Numbers are not strings or sequences and Python will raise an error
 if you try to perform an index operation on a number. In the <a href="03-types-conversion.html">next lesson on types and type
@@ -820,7 +820,7 @@ <h3 class="callout-title">Choosing a Name<a class="anchor" aria-label="anchor" h
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p><code>minutes</code> is better because <code>min</code> might mean
 something like “minimum” (and actually is an existing built-in function
@@ -852,7 +852,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -900,7 +900,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Solutions</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>
 <code>species_name[2:8]</code> returns the substring
diff --git a/03-types-conversion.html b/03-types-conversion.html
index c1e494270..0bbef534d 100644
--- a/03-types-conversion.html
+++ b/03-types-conversion.html
@@ -658,7 +658,7 @@ <h3 class="callout-title">Fractions<a class="anchor" aria-label="anchor" href="#
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>It is a floating-point number (often abbreviated “float”). It is
 possible to find out by using the built-in function
@@ -694,7 +694,7 @@ <h3 class="callout-title">Automatic Type Conversion<a class="anchor" aria-label=
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>It is a float: integers are automatically converted to floats as
 necessary.</p>
@@ -740,7 +740,7 @@ <h3 class="callout-title">Choose a Type<a class="anchor" aria-label="anchor" hre
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>The answers to the questions are:</p>
 <ol style="list-style-type: decimal"><li>Integer, since the number of days would lie between 1 and 365.</li>
@@ -796,7 +796,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>We want the minimum number of surveys that reaches everyone once,
 which is the rounded up value of
@@ -880,7 +880,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>What do you expect this program to do? It would not be so
 unreasonable to expect the Python 3 <code>int</code> command to convert
@@ -949,7 +949,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>Answer: 1 and 4</p>
 </div>
@@ -994,7 +994,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>Standard mathematics treatments typically use <code>i</code> to
 denote an imaginary number. However, from media reports it was an early
diff --git a/07-reading-tabular.html b/07-reading-tabular.html
index 7f843d107..0c390d33b 100644
--- a/07-reading-tabular.html
+++ b/07-reading-tabular.html
@@ -691,7 +691,7 @@ <h3 class="callout-title">Reading Other Data<a class="anchor" aria-label="anchor
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>To read in a CSV, we use <code>pd.read_csv</code> and pass the
 filename <code>'data/gapminder_gdp_americas.csv'</code> to it. We also
@@ -733,7 +733,7 @@ <h3 class="callout-title">Inspecting Data<a class="anchor" aria-label="anchor" h
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>We can check out the first five rows of <code>data_americas</code>
 by executing <code>data_americas.head()</code> which lets us view the
@@ -864,7 +864,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
 <div class="accordion-body">
 <p>We need to specify the path to the file of interest in the call to
 <code>pd.read_csv</code>. We first need to ‘jump’ out of the folder
@@ -902,7 +902,7 @@ <h3 class="callout-title">Writing Data<a class="anchor" aria-label="anchor" href
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
 <div class="accordion-body">
 <p>In order to write the DataFrame <code>data_americas</code> to a file
 called <code>processed.csv</code>, execute the following command:</p>
diff --git a/08-data-frames.html b/08-data-frames.html
index d63daf68b..7ae1354bb 100644
--- a/08-data-frames.html
+++ b/08-data-frames.html
@@ -781,7 +781,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>The selection can be done by using the labels for both the row
 (“Serbia”) and the column (“gdpPercap_2007”):</p>
@@ -825,7 +825,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>No, they do not produce the same output! The output of the first
 statement is:</p>
@@ -884,7 +884,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>Let’s go through this piece of code line by line.</p>
 <div class="codewrapper sourceCode" id="cb32">
@@ -966,7 +966,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>For each column in <code>data</code>, <code>idxmin</code> will return
 the index value corresponding to each column’s minimum;
@@ -1002,7 +1002,7 @@ <h3 class="callout-title">Practice with Selection<a class="anchor" aria-label="a
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>1:</p>
 <div class="codewrapper sourceCode" id="cb38">
@@ -1065,7 +1065,7 @@ <h3 class="callout-title">Many Ways of Access<a class="anchor" aria-label="ancho
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>1. Access a single column:</p>
 <div class="codewrapper sourceCode" id="cb42">
@@ -1251,7 +1251,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <p>Among many choices, <code>dir()</code> lists the
 <code>median()</code> function as a possibility. Thus,</p>
diff --git a/11-lists.html b/11-lists.html
index b6c661e82..ff0e65c9b 100644
--- a/11-lists.html
+++ b/11-lists.html
@@ -663,7 +663,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb22">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -698,7 +698,7 @@ <h3 class="callout-title">How Large is a Slice?<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>The list <code>values[start:stop]</code> has up to
 <code>stop - start</code> elements. For example,
@@ -742,7 +742,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>
 <a href="https://docs.python.org/3/library/stdtypes.html#list" class="external-link"><code>list('some string')</code></a>
@@ -789,7 +789,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>The program prints <code>m</code>.</p>
 <ol style="list-style-type: decimal"><li>Python interprets a negative index as starting from the end (as
@@ -833,7 +833,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>The program prints</p>
 <div class="codewrapper sourceCode" id="cb27">
@@ -877,7 +877,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -926,7 +926,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <p>Program A prints</p>
 <div class="codewrapper">
@@ -985,7 +985,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <p>Program A prints</p>
 <div class="codewrapper">
diff --git a/14-looping-data-sets.html b/14-looping-data-sets.html
index a3e444073..ee6911841 100644
--- a/14-looping-data-sets.html
+++ b/14-looping-data-sets.html
@@ -390,7 +390,7 @@ <h2 class="accordion-header" id="flush-headingTwelve">
       </div>
       <hr></nav><main id="main-content" class="main-content"><div class="container lesson-content">
         <h1>Looping Over Data Sets</h1>
-        <p>Last updated on 2023-05-02 |
+        <p>Last updated on 2024-03-05 |
         
         <a href="https://github.com/swcarpentry/python-novice-gapminder/edit/main/episodes/14-looping-data-sets.md" class="external-link">Edit this page <i aria-hidden="true" data-feather="edit"></i></a></p>
         
@@ -623,7 +623,10 @@ <h3 class="callout-title">Comparing Data<a class="anchor" aria-label="anchor" hr
 </h3>
 <div class="callout-content">
 <p>Write a program that reads in the regional data sets and plots the
-average GDP per capita for each region over time in a single chart.</p>
+average GDP per capita for each region over time in a single chart.
+Pandas will raise an error if it encounters non-numeric columns in a
+dataframe computation so you may need to either filter out those columns
+or tell pandas to ignore them.</p>
 </div>
 </div>
 </div>
@@ -650,10 +653,19 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <span id="cb11-8"><a href="#cb11-8" tabindex="-1"></a>    <span class="co"># we will split the string using the split method and `_` as our separator,</span></span>
 <span id="cb11-9"><a href="#cb11-9" tabindex="-1"></a>    <span class="co"># retrieve the last string in the list that split returns (`&lt;region&gt;.csv`), </span></span>
 <span id="cb11-10"><a href="#cb11-10" tabindex="-1"></a>    <span class="co"># and then remove the `.csv` extension from that string.</span></span>
-<span id="cb11-11"><a href="#cb11-11" tabindex="-1"></a>    region <span class="op">=</span> filename.split(<span class="st">'_'</span>)[<span class="op">-</span><span class="dv">1</span>][:<span class="op">-</span><span class="dv">4</span>] </span>
-<span id="cb11-12"><a href="#cb11-12" tabindex="-1"></a>    dataframe.mean().plot(ax<span class="op">=</span>ax, label<span class="op">=</span>region)</span>
-<span id="cb11-13"><a href="#cb11-13" tabindex="-1"></a>plt.legend()</span>
-<span id="cb11-14"><a href="#cb11-14" tabindex="-1"></a>plt.show()</span></code></pre>
+<span id="cb11-11"><a href="#cb11-11" tabindex="-1"></a>    <span class="co"># </span><span class="al">NOTE</span><span class="co">: the pathlib module covered in the next callout also offers</span></span>
+<span id="cb11-12"><a href="#cb11-12" tabindex="-1"></a>    <span class="co"># convenient abstractions for working with filesystem paths and could solve this as well:</span></span>
+<span id="cb11-13"><a href="#cb11-13" tabindex="-1"></a>    <span class="co"># from pathlib import Path</span></span>
+<span id="cb11-14"><a href="#cb11-14" tabindex="-1"></a>    <span class="co"># region = Path(filename).stem.split('_')[-1]</span></span>
+<span id="cb11-15"><a href="#cb11-15" tabindex="-1"></a>    region <span class="op">=</span> filename.split(<span class="st">'_'</span>)[<span class="op">-</span><span class="dv">1</span>][:<span class="op">-</span><span class="dv">4</span>] </span>
+<span id="cb11-16"><a href="#cb11-16" tabindex="-1"></a>    <span class="co"># pandas raises errors when it encounters non-numeric columns in a dataframe computation</span></span>
+<span id="cb11-17"><a href="#cb11-17" tabindex="-1"></a>    <span class="co"># but we can tell pandas to ignore them with the `numeric_only` parameter</span></span>
+<span id="cb11-18"><a href="#cb11-18" tabindex="-1"></a>    dataframe.mean(numeric_only<span class="op">=</span><span class="va">True</span>).plot(ax<span class="op">=</span>ax, label<span class="op">=</span>region)</span>
+<span id="cb11-19"><a href="#cb11-19" tabindex="-1"></a>    <span class="co"># </span><span class="al">NOTE</span><span class="co">: another way of doing this selects just the columns with gdp in their name using the filter method</span></span>
+<span id="cb11-20"><a href="#cb11-20" tabindex="-1"></a>    <span class="co"># dataframe.filter(like="gdp").mean().plot(ax=ax, label=region)</span></span>
+<span id="cb11-21"><a href="#cb11-21" tabindex="-1"></a></span>
+<span id="cb11-22"><a href="#cb11-22" tabindex="-1"></a>plt.legend()</span>
+<span id="cb11-23"><a href="#cb11-23" tabindex="-1"></a>plt.show()</span></code></pre>
 </div>
 </div>
 </div>
@@ -687,9 +699,8 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <span><span class="va">gapminder_gdp_africa</span></span>
 <span><span class="va">.csv</span></span></code></pre>
 </div>
-<p><strong>Hint:</strong> It is possible to check all available
-attributes and methods on the <code>Path</code> object with the
-<code>dir()</code> function!</p>
+<p><strong>Hint:</strong> Check all available attributes and methods on
+the <code>Path</code> object with the <code>dir()</code> function.</p>
 </div>
 </div>
 </div>
@@ -768,7 +779,7 @@ <h3 class="callout-title">Key Points<a class="anchor" aria-label="anchor" href="
   "url": "https://swcarpentry.github.io/python-novice-gapminder/14-looping-data-sets.html",
   "identifier": "https://swcarpentry.github.io/python-novice-gapminder/14-looping-data-sets.html",
   "dateCreated": "2016-01-07",
-  "dateModified": "2023-05-02",
+  "dateModified": "2024-03-05",
   "datePublished": "2024-03-05"
 }
 
diff --git a/16-writing-functions.html b/16-writing-functions.html
index f88dfce9b..2a18f5e02 100644
--- a/16-writing-functions.html
+++ b/16-writing-functions.html
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 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
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 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
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-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
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 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li><p>The problem with the example is that the function
 <code>print_time()</code> is defined <em>after</em> the call to the
@@ -768,7 +768,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
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 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
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 <div class="codewrapper sourceCode" id="cb27">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -873,7 +873,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li><code>2003/2/1</code></li>
 <li>We saw examples of using <em>named arguments</em> when working with
@@ -957,7 +957,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb34">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1033,7 +1033,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>The average GDP for Japan across the years reported for the 1980s is
 computed with:</li>
@@ -1132,7 +1132,7 @@ <h3 class="callout-title">Simulating a dynamical system<a class="anchor" aria-la
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution9" aria-expanded="false" aria-controls="collapseSolution9">
   <h4 class="accordion-header" id="headingSolution9">Show me the solution</h4>
 </button>
-<div id="collapseSolution9" class="accordion-collapse collapse" aria-labelledby="headingSolution9" data-bs-parent="#accordionSolution9">
+<div id="collapseSolution9" class="accordion-collapse collapse" data-bs-parent="#accordionSolution9" aria-labelledby="headingSolution9">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li><div class="codewrapper sourceCode" id="cb43">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
diff --git a/aio.html b/aio.html
index 54c1083f7..ea1b06c62 100644
--- a/aio.html
+++ b/aio.html
@@ -1593,7 +1593,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1638,7 +1638,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb20">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1678,7 +1678,7 @@ <h3 class="callout-title">Challenge<a class="anchor" aria-label="anchor" href="#
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>Numbers are not strings or sequences and Python will raise an error
 if you try to perform an index operation on a number. In the <a href="03-types-conversion.html">next lesson on types and type
@@ -1736,7 +1736,7 @@ <h3 class="callout-title">Choosing a Name<a class="anchor" aria-label="anchor" h
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p><code>minutes</code> is better because <code>min</code> might mean
 something like “minimum” (and actually is an existing built-in function
@@ -1768,7 +1768,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1818,7 +1818,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Solutions</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>
@@ -2179,7 +2179,7 @@ <h3 class="callout-title">Fractions<a class="anchor" aria-label="anchor" href="#
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>It is a floating-point number (often abbreviated “float”). It is
 possible to find out by using the built-in function
@@ -2215,7 +2215,7 @@ <h3 class="callout-title">Automatic Type Conversion<a class="anchor" aria-label=
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>It is a float: integers are automatically converted to floats as
 necessary.</p>
@@ -2263,7 +2263,7 @@ <h3 class="callout-title">Choose a Type<a class="anchor" aria-label="anchor" hre
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>The answers to the questions are:</p>
 <ol style="list-style-type: decimal">
@@ -2321,7 +2321,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>We want the minimum number of surveys that reaches everyone once,
 which is the rounded up value of
@@ -2405,7 +2405,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>What do you expect this program to do? It would not be so
 unreasonable to expect the Python 3 <code>int</code> command to convert
@@ -2476,7 +2476,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>Answer: 1 and 4</p>
 </div>
@@ -2523,7 +2523,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
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   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>Standard mathematics treatments typically use <code>i</code> to
@@ -4142,7 +4142,7 @@ <h3 class="callout-title">Reading Other Data<a class="anchor" aria-label="anchor
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>To read in a CSV, we use <code>pd.read_csv</code> and pass the
 filename <code>'data/gapminder_gdp_americas.csv'</code> to it. We also
@@ -4186,7 +4186,7 @@ <h3 class="callout-title">Inspecting Data<a class="anchor" aria-label="anchor" h
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>We can check out the first five rows of <code>data_americas</code>
@@ -4321,7 +4321,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
 <div class="accordion-body">
 <p>We need to specify the path to the file of interest in the call to
 <code>pd.read_csv</code>. We first need to ‘jump’ out of the folder
@@ -4359,7 +4359,7 @@ <h3 class="callout-title">Writing Data<a class="anchor" aria-label="anchor" href
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
 <div class="accordion-body">
 <p>In order to write the DataFrame <code>data_americas</code> to a file
 called <code>processed.csv</code>, execute the following command:</p>
@@ -4823,7 +4823,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>The selection can be done by using the labels for both the row
 (“Serbia”) and the column (“gdpPercap_2007”):</p>
@@ -4869,7 +4869,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>No, they do not produce the same output! The output of the first
 statement is:</p>
@@ -4928,7 +4928,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>Let’s go through this piece of code line by line.</p>
 <div class="codewrapper sourceCode" id="cb32">
@@ -5010,7 +5010,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>For each column in <code>data</code>, <code>idxmin</code> will return
 the index value corresponding to each column’s minimum;
@@ -5048,7 +5048,7 @@ <h3 class="callout-title">Practice with Selection<a class="anchor" aria-label="a
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>1:</p>
 <div class="codewrapper sourceCode" id="cb38">
@@ -5113,7 +5113,7 @@ <h3 class="callout-title">Many Ways of Access<a class="anchor" aria-label="ancho
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>1. Access a single column:</p>
 <div class="codewrapper sourceCode" id="cb42">
@@ -5299,7 +5299,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <p>Among many choices, <code>dir()</code> lists the
 <code>median()</code> function as a possibility. Thus,</p>
@@ -6174,7 +6174,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb22">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -6209,7 +6209,7 @@ <h3 class="callout-title">How Large is a Slice?<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>The list <code>values[start:stop]</code> has up to
 <code>stop - start</code> elements. For example,
@@ -6255,7 +6255,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>
@@ -6306,7 +6306,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>The program prints <code>m</code>.</p>
 <ol style="list-style-type: decimal">
@@ -6354,7 +6354,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>The program prints</p>
 <div class="codewrapper sourceCode" id="cb27">
@@ -6400,7 +6400,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -6449,7 +6449,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <p>Program A prints</p>
 <div class="codewrapper">
@@ -6508,7 +6508,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <p>Program A prints</p>
 <div class="codewrapper">
@@ -7886,7 +7886,7 @@ <h3 class="callout-title">Key Points<a class="anchor" aria-label="anchor" href="
 </div>
 </section></section><section id="aio-14-looping-data-sets"><p>Content from <a href="14-looping-data-sets.html">Looping Over Data Sets</a></p>
 <hr>
-<p>Last updated on 2023-05-02 |
+<p>Last updated on 2024-03-05 |
         
         <a href="https://github.com/swcarpentry/python-novice-gapminder/edit/main/episodes/14-looping-data-sets.md" class="external-link">Edit this page <i aria-hidden="true" data-feather="edit"></i></a></p>
 <div class="text-end">
@@ -8132,7 +8132,10 @@ <h3 class="callout-title">Comparing Data<a class="anchor" aria-label="anchor" hr
 </h3>
 <div class="callout-content">
 <p>Write a program that reads in the regional data sets and plots the
-average GDP per capita for each region over time in a single chart.</p>
+average GDP per capita for each region over time in a single chart.
+Pandas will raise an error if it encounters non-numeric columns in a
+dataframe computation so you may need to either filter out those columns
+or tell pandas to ignore them.</p>
 </div>
 </div>
 </div>
@@ -8159,10 +8162,19 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <span id="cb11-8"><a href="#cb11-8" tabindex="-1"></a>    <span class="co"># we will split the string using the split method and `_` as our separator,</span></span>
 <span id="cb11-9"><a href="#cb11-9" tabindex="-1"></a>    <span class="co"># retrieve the last string in the list that split returns (`&lt;region&gt;.csv`), </span></span>
 <span id="cb11-10"><a href="#cb11-10" tabindex="-1"></a>    <span class="co"># and then remove the `.csv` extension from that string.</span></span>
-<span id="cb11-11"><a href="#cb11-11" tabindex="-1"></a>    region <span class="op">=</span> filename.split(<span class="st">'_'</span>)[<span class="op">-</span><span class="dv">1</span>][:<span class="op">-</span><span class="dv">4</span>] </span>
-<span id="cb11-12"><a href="#cb11-12" tabindex="-1"></a>    dataframe.mean().plot(ax<span class="op">=</span>ax, label<span class="op">=</span>region)</span>
-<span id="cb11-13"><a href="#cb11-13" tabindex="-1"></a>plt.legend()</span>
-<span id="cb11-14"><a href="#cb11-14" tabindex="-1"></a>plt.show()</span></code></pre>
+<span id="cb11-11"><a href="#cb11-11" tabindex="-1"></a>    <span class="co"># </span><span class="al">NOTE</span><span class="co">: the pathlib module covered in the next callout also offers</span></span>
+<span id="cb11-12"><a href="#cb11-12" tabindex="-1"></a>    <span class="co"># convenient abstractions for working with filesystem paths and could solve this as well:</span></span>
+<span id="cb11-13"><a href="#cb11-13" tabindex="-1"></a>    <span class="co"># from pathlib import Path</span></span>
+<span id="cb11-14"><a href="#cb11-14" tabindex="-1"></a>    <span class="co"># region = Path(filename).stem.split('_')[-1]</span></span>
+<span id="cb11-15"><a href="#cb11-15" tabindex="-1"></a>    region <span class="op">=</span> filename.split(<span class="st">'_'</span>)[<span class="op">-</span><span class="dv">1</span>][:<span class="op">-</span><span class="dv">4</span>] </span>
+<span id="cb11-16"><a href="#cb11-16" tabindex="-1"></a>    <span class="co"># pandas raises errors when it encounters non-numeric columns in a dataframe computation</span></span>
+<span id="cb11-17"><a href="#cb11-17" tabindex="-1"></a>    <span class="co"># but we can tell pandas to ignore them with the `numeric_only` parameter</span></span>
+<span id="cb11-18"><a href="#cb11-18" tabindex="-1"></a>    dataframe.mean(numeric_only<span class="op">=</span><span class="va">True</span>).plot(ax<span class="op">=</span>ax, label<span class="op">=</span>region)</span>
+<span id="cb11-19"><a href="#cb11-19" tabindex="-1"></a>    <span class="co"># </span><span class="al">NOTE</span><span class="co">: another way of doing this selects just the columns with gdp in their name using the filter method</span></span>
+<span id="cb11-20"><a href="#cb11-20" tabindex="-1"></a>    <span class="co"># dataframe.filter(like="gdp").mean().plot(ax=ax, label=region)</span></span>
+<span id="cb11-21"><a href="#cb11-21" tabindex="-1"></a></span>
+<span id="cb11-22"><a href="#cb11-22" tabindex="-1"></a>plt.legend()</span>
+<span id="cb11-23"><a href="#cb11-23" tabindex="-1"></a>plt.show()</span></code></pre>
 </div>
 </div>
 </div>
@@ -8197,9 +8209,8 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <span><span class="va">gapminder_gdp_africa</span></span>
 <span><span class="va">.csv</span></span></code></pre>
 </div>
-<p><strong>Hint:</strong> It is possible to check all available
-attributes and methods on the <code>Path</code> object with the
-<code>dir()</code> function!</p>
+<p><strong>Hint:</strong> Check all available attributes and methods on
+the <code>Path</code> object with the <code>dir()</code> function.</p>
 </div>
 </div>
 </div>
@@ -8500,7 +8511,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb16">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8539,7 +8550,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8614,7 +8625,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li><p>The problem with the example is that the function
@@ -8663,7 +8674,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb25">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8706,7 +8717,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb27">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8770,7 +8781,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li><code>2003/2/1</code></li>
@@ -8858,7 +8869,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb34">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8940,7 +8951,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>The average GDP for Japan across the years reported for the 1980s is
@@ -9049,7 +9060,7 @@ <h3 class="callout-title">Simulating a dynamical system<a class="anchor" aria-la
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution9" aria-expanded="false" aria-controls="collapseSolution9">
   <h4 class="accordion-header" id="headingSolution9">Show me the solution</h4>
 </button>
-<div id="collapseSolution9" class="accordion-collapse collapse" aria-labelledby="headingSolution9" data-bs-parent="#accordionSolution9">
+<div id="collapseSolution9" class="accordion-collapse collapse" data-bs-parent="#accordionSolution9" aria-labelledby="headingSolution9">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li><div class="codewrapper sourceCode" id="cb43">
diff --git a/instructor/02-variables.html b/instructor/02-variables.html
index 39b99623c..5e821e320 100644
--- a/instructor/02-variables.html
+++ b/instructor/02-variables.html
@@ -681,7 +681,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -726,7 +726,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb20">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -766,7 +766,7 @@ <h3 class="callout-title">Challenge<a class="anchor" aria-label="anchor" href="#
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>Numbers are not strings or sequences and Python will raise an error
 if you try to perform an index operation on a number. In the <a href="03-types-conversion.html">next lesson on types and type
@@ -822,7 +822,7 @@ <h3 class="callout-title">Choosing a Name<a class="anchor" aria-label="anchor" h
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p><code>minutes</code> is better because <code>min</code> might mean
 something like “minimum” (and actually is an existing built-in function
@@ -854,7 +854,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -902,7 +902,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Solutions</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>
 <code>species_name[2:8]</code> returns the substring
diff --git a/instructor/03-types-conversion.html b/instructor/03-types-conversion.html
index d5a51a4a9..b38ae63b5 100644
--- a/instructor/03-types-conversion.html
+++ b/instructor/03-types-conversion.html
@@ -660,7 +660,7 @@ <h3 class="callout-title">Fractions<a class="anchor" aria-label="anchor" href="#
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>It is a floating-point number (often abbreviated “float”). It is
 possible to find out by using the built-in function
@@ -696,7 +696,7 @@ <h3 class="callout-title">Automatic Type Conversion<a class="anchor" aria-label=
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>It is a float: integers are automatically converted to floats as
 necessary.</p>
@@ -742,7 +742,7 @@ <h3 class="callout-title">Choose a Type<a class="anchor" aria-label="anchor" hre
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>The answers to the questions are:</p>
 <ol style="list-style-type: decimal"><li>Integer, since the number of days would lie between 1 and 365.</li>
@@ -798,7 +798,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>We want the minimum number of surveys that reaches everyone once,
 which is the rounded up value of
@@ -882,7 +882,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>What do you expect this program to do? It would not be so
 unreasonable to expect the Python 3 <code>int</code> command to convert
@@ -951,7 +951,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>Answer: 1 and 4</p>
 </div>
@@ -996,7 +996,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>Standard mathematics treatments typically use <code>i</code> to
 denote an imaginary number. However, from media reports it was an early
diff --git a/instructor/07-reading-tabular.html b/instructor/07-reading-tabular.html
index bd01ebac2..59a4cd1c1 100644
--- a/instructor/07-reading-tabular.html
+++ b/instructor/07-reading-tabular.html
@@ -693,7 +693,7 @@ <h3 class="callout-title">Reading Other Data<a class="anchor" aria-label="anchor
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>To read in a CSV, we use <code>pd.read_csv</code> and pass the
 filename <code>'data/gapminder_gdp_americas.csv'</code> to it. We also
@@ -735,7 +735,7 @@ <h3 class="callout-title">Inspecting Data<a class="anchor" aria-label="anchor" h
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>We can check out the first five rows of <code>data_americas</code>
 by executing <code>data_americas.head()</code> which lets us view the
@@ -866,7 +866,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
 <div class="accordion-body">
 <p>We need to specify the path to the file of interest in the call to
 <code>pd.read_csv</code>. We first need to ‘jump’ out of the folder
@@ -904,7 +904,7 @@ <h3 class="callout-title">Writing Data<a class="anchor" aria-label="anchor" href
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
 <div class="accordion-body">
 <p>In order to write the DataFrame <code>data_americas</code> to a file
 called <code>processed.csv</code>, execute the following command:</p>
diff --git a/instructor/08-data-frames.html b/instructor/08-data-frames.html
index 453caf7df..43e432965 100644
--- a/instructor/08-data-frames.html
+++ b/instructor/08-data-frames.html
@@ -680,7 +680,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
   <h3 class="accordion-header" id="headingInstructor1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="edit-2"></i></div>Instructor Note</h3>
 </button>
-<div id="collapseInstructor1" class="accordion-collapse collapse" aria-labelledby="headingInstructor1" data-bs-parent="#accordionInstructor1">
+<div id="collapseInstructor1" class="accordion-collapse collapse" data-bs-parent="#accordionInstructor1" aria-labelledby="headingInstructor1">
 <div class="accordion-body">
 <p>Learners often struggle here, many may not work with financial data
 and concepts so they find the example concepts difficult to get their
@@ -802,7 +802,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>The selection can be done by using the labels for both the row
 (“Serbia”) and the column (“gdpPercap_2007”):</p>
@@ -846,7 +846,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>No, they do not produce the same output! The output of the first
 statement is:</p>
@@ -905,7 +905,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>Let’s go through this piece of code line by line.</p>
 <div class="codewrapper sourceCode" id="cb32">
@@ -987,7 +987,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>For each column in <code>data</code>, <code>idxmin</code> will return
 the index value corresponding to each column’s minimum;
@@ -1023,7 +1023,7 @@ <h3 class="callout-title">Practice with Selection<a class="anchor" aria-label="a
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>1:</p>
 <div class="codewrapper sourceCode" id="cb38">
@@ -1086,7 +1086,7 @@ <h3 class="callout-title">Many Ways of Access<a class="anchor" aria-label="ancho
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>1. Access a single column:</p>
 <div class="codewrapper sourceCode" id="cb42">
@@ -1272,7 +1272,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <p>Among many choices, <code>dir()</code> lists the
 <code>median()</code> function as a possibility. Thus,</p>
diff --git a/instructor/11-lists.html b/instructor/11-lists.html
index ea0ab7769..9b3c64158 100644
--- a/instructor/11-lists.html
+++ b/instructor/11-lists.html
@@ -665,7 +665,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb22">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -700,7 +700,7 @@ <h3 class="callout-title">How Large is a Slice?<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>The list <code>values[start:stop]</code> has up to
 <code>stop - start</code> elements. For example,
@@ -744,7 +744,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>
 <a href="https://docs.python.org/3/library/stdtypes.html#list" class="external-link"><code>list('some string')</code></a>
@@ -791,7 +791,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>The program prints <code>m</code>.</p>
 <ol style="list-style-type: decimal"><li>Python interprets a negative index as starting from the end (as
@@ -835,7 +835,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>The program prints</p>
 <div class="codewrapper sourceCode" id="cb27">
@@ -879,7 +879,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -928,7 +928,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <p>Program A prints</p>
 <div class="codewrapper">
@@ -987,7 +987,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <p>Program A prints</p>
 <div class="codewrapper">
diff --git a/instructor/14-looping-data-sets.html b/instructor/14-looping-data-sets.html
index 85cf59905..7720dd024 100644
--- a/instructor/14-looping-data-sets.html
+++ b/instructor/14-looping-data-sets.html
@@ -390,7 +390,7 @@ <h2 class="accordion-header" id="flush-headingTwelve">
       </div>
       <hr></nav><main id="main-content" class="main-content"><div class="container lesson-content">
         <h1>Looping Over Data Sets</h1>
-        <p>Last updated on 2023-05-02 |
+        <p>Last updated on 2024-03-05 |
         
         <a href="https://github.com/swcarpentry/python-novice-gapminder/edit/main/episodes/14-looping-data-sets.md" class="external-link">Edit this page <i aria-hidden="true" data-feather="edit"></i></a></p>
         
@@ -625,7 +625,10 @@ <h3 class="callout-title">Comparing Data<a class="anchor" aria-label="anchor" hr
 </h3>
 <div class="callout-content">
 <p>Write a program that reads in the regional data sets and plots the
-average GDP per capita for each region over time in a single chart.</p>
+average GDP per capita for each region over time in a single chart.
+Pandas will raise an error if it encounters non-numeric columns in a
+dataframe computation so you may need to either filter out those columns
+or tell pandas to ignore them.</p>
 </div>
 </div>
 </div>
@@ -652,10 +655,19 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <span id="cb11-8"><a href="#cb11-8" tabindex="-1"></a>    <span class="co"># we will split the string using the split method and `_` as our separator,</span></span>
 <span id="cb11-9"><a href="#cb11-9" tabindex="-1"></a>    <span class="co"># retrieve the last string in the list that split returns (`&lt;region&gt;.csv`), </span></span>
 <span id="cb11-10"><a href="#cb11-10" tabindex="-1"></a>    <span class="co"># and then remove the `.csv` extension from that string.</span></span>
-<span id="cb11-11"><a href="#cb11-11" tabindex="-1"></a>    region <span class="op">=</span> filename.split(<span class="st">'_'</span>)[<span class="op">-</span><span class="dv">1</span>][:<span class="op">-</span><span class="dv">4</span>] </span>
-<span id="cb11-12"><a href="#cb11-12" tabindex="-1"></a>    dataframe.mean().plot(ax<span class="op">=</span>ax, label<span class="op">=</span>region)</span>
-<span id="cb11-13"><a href="#cb11-13" tabindex="-1"></a>plt.legend()</span>
-<span id="cb11-14"><a href="#cb11-14" tabindex="-1"></a>plt.show()</span></code></pre>
+<span id="cb11-11"><a href="#cb11-11" tabindex="-1"></a>    <span class="co"># </span><span class="al">NOTE</span><span class="co">: the pathlib module covered in the next callout also offers</span></span>
+<span id="cb11-12"><a href="#cb11-12" tabindex="-1"></a>    <span class="co"># convenient abstractions for working with filesystem paths and could solve this as well:</span></span>
+<span id="cb11-13"><a href="#cb11-13" tabindex="-1"></a>    <span class="co"># from pathlib import Path</span></span>
+<span id="cb11-14"><a href="#cb11-14" tabindex="-1"></a>    <span class="co"># region = Path(filename).stem.split('_')[-1]</span></span>
+<span id="cb11-15"><a href="#cb11-15" tabindex="-1"></a>    region <span class="op">=</span> filename.split(<span class="st">'_'</span>)[<span class="op">-</span><span class="dv">1</span>][:<span class="op">-</span><span class="dv">4</span>] </span>
+<span id="cb11-16"><a href="#cb11-16" tabindex="-1"></a>    <span class="co"># pandas raises errors when it encounters non-numeric columns in a dataframe computation</span></span>
+<span id="cb11-17"><a href="#cb11-17" tabindex="-1"></a>    <span class="co"># but we can tell pandas to ignore them with the `numeric_only` parameter</span></span>
+<span id="cb11-18"><a href="#cb11-18" tabindex="-1"></a>    dataframe.mean(numeric_only<span class="op">=</span><span class="va">True</span>).plot(ax<span class="op">=</span>ax, label<span class="op">=</span>region)</span>
+<span id="cb11-19"><a href="#cb11-19" tabindex="-1"></a>    <span class="co"># </span><span class="al">NOTE</span><span class="co">: another way of doing this selects just the columns with gdp in their name using the filter method</span></span>
+<span id="cb11-20"><a href="#cb11-20" tabindex="-1"></a>    <span class="co"># dataframe.filter(like="gdp").mean().plot(ax=ax, label=region)</span></span>
+<span id="cb11-21"><a href="#cb11-21" tabindex="-1"></a></span>
+<span id="cb11-22"><a href="#cb11-22" tabindex="-1"></a>plt.legend()</span>
+<span id="cb11-23"><a href="#cb11-23" tabindex="-1"></a>plt.show()</span></code></pre>
 </div>
 </div>
 </div>
@@ -689,9 +701,8 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <span><span class="va">gapminder_gdp_africa</span></span>
 <span><span class="va">.csv</span></span></code></pre>
 </div>
-<p><strong>Hint:</strong> It is possible to check all available
-attributes and methods on the <code>Path</code> object with the
-<code>dir()</code> function!</p>
+<p><strong>Hint:</strong> Check all available attributes and methods on
+the <code>Path</code> object with the <code>dir()</code> function.</p>
 </div>
 </div>
 </div>
@@ -770,7 +781,7 @@ <h3 class="callout-title">Key Points<a class="anchor" aria-label="anchor" href="
   "url": "https://swcarpentry.github.io/python-novice-gapminder/instructor/14-looping-data-sets.html",
   "identifier": "https://swcarpentry.github.io/python-novice-gapminder/instructor/14-looping-data-sets.html",
   "dateCreated": "2016-01-07",
-  "dateModified": "2023-05-02",
+  "dateModified": "2024-03-05",
   "datePublished": "2024-03-05"
 }
 
diff --git a/instructor/16-writing-functions.html b/instructor/16-writing-functions.html
index 184a1307e..bc28d0acb 100644
--- a/instructor/16-writing-functions.html
+++ b/instructor/16-writing-functions.html
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 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
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 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
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 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li><p>The problem with the example is that the function
 <code>print_time()</code> is defined <em>after</em> the call to the
@@ -770,7 +770,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
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@@ -813,7 +813,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
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 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
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@@ -875,7 +875,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li><code>2003/2/1</code></li>
 <li>We saw examples of using <em>named arguments</em> when working with
@@ -959,7 +959,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
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@@ -1035,7 +1035,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li>The average GDP for Japan across the years reported for the 1980s is
 computed with:</li>
@@ -1134,7 +1134,7 @@ <h3 class="callout-title">Simulating a dynamical system<a class="anchor" aria-la
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution9" aria-expanded="false" aria-controls="collapseSolution9">
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 </button>
-<div id="collapseSolution9" class="accordion-collapse collapse" aria-labelledby="headingSolution9" data-bs-parent="#accordionSolution9">
+<div id="collapseSolution9" class="accordion-collapse collapse" data-bs-parent="#accordionSolution9" aria-labelledby="headingSolution9">
 <div class="accordion-body">
 <ol style="list-style-type: decimal"><li><div class="codewrapper sourceCode" id="cb43">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
diff --git a/instructor/aio.html b/instructor/aio.html
index 6fb7eaf27..6806bbb9f 100644
--- a/instructor/aio.html
+++ b/instructor/aio.html
@@ -1599,7 +1599,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1644,7 +1644,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
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 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb20">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1684,7 +1684,7 @@ <h3 class="callout-title">Challenge<a class="anchor" aria-label="anchor" href="#
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 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>Numbers are not strings or sequences and Python will raise an error
 if you try to perform an index operation on a number. In the <a href="03-types-conversion.html">next lesson on types and type
@@ -1742,7 +1742,7 @@ <h3 class="callout-title">Choosing a Name<a class="anchor" aria-label="anchor" h
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p><code>minutes</code> is better because <code>min</code> might mean
 something like “minimum” (and actually is an existing built-in function
@@ -1774,7 +1774,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1824,7 +1824,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
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   <h4 class="accordion-header" id="headingSolution6">Solutions</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>
@@ -2186,7 +2186,7 @@ <h3 class="callout-title">Fractions<a class="anchor" aria-label="anchor" href="#
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>It is a floating-point number (often abbreviated “float”). It is
 possible to find out by using the built-in function
@@ -2222,7 +2222,7 @@ <h3 class="callout-title">Automatic Type Conversion<a class="anchor" aria-label=
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>It is a float: integers are automatically converted to floats as
 necessary.</p>
@@ -2270,7 +2270,7 @@ <h3 class="callout-title">Choose a Type<a class="anchor" aria-label="anchor" hre
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>The answers to the questions are:</p>
 <ol style="list-style-type: decimal">
@@ -2328,7 +2328,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>We want the minimum number of surveys that reaches everyone once,
 which is the rounded up value of
@@ -2412,7 +2412,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>What do you expect this program to do? It would not be so
 unreasonable to expect the Python 3 <code>int</code> command to convert
@@ -2483,7 +2483,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>Answer: 1 and 4</p>
 </div>
@@ -2530,7 +2530,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>Standard mathematics treatments typically use <code>i</code> to
@@ -4153,7 +4153,7 @@ <h3 class="callout-title">Reading Other Data<a class="anchor" aria-label="anchor
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
 <div class="accordion-body">
 <p>To read in a CSV, we use <code>pd.read_csv</code> and pass the
 filename <code>'data/gapminder_gdp_americas.csv'</code> to it. We also
@@ -4197,7 +4197,7 @@ <h3 class="callout-title">Inspecting Data<a class="anchor" aria-label="anchor" h
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>We can check out the first five rows of <code>data_americas</code>
@@ -4332,7 +4332,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
 <div class="accordion-body">
 <p>We need to specify the path to the file of interest in the call to
 <code>pd.read_csv</code>. We first need to ‘jump’ out of the folder
@@ -4370,7 +4370,7 @@ <h3 class="callout-title">Writing Data<a class="anchor" aria-label="anchor" href
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
 <div class="accordion-body">
 <p>In order to write the DataFrame <code>data_americas</code> to a file
 called <code>processed.csv</code>, execute the following command:</p>
@@ -4730,7 +4730,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
   <h3 class="accordion-header" id="headingInstructor1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="edit-2"></i></div>Instructor Note</h3>
 </button>
-<div id="collapseInstructor1" class="accordion-collapse collapse" aria-labelledby="headingInstructor1" data-bs-parent="#accordionInstructor1">
+<div id="collapseInstructor1" class="accordion-collapse collapse" data-bs-parent="#accordionInstructor1" aria-labelledby="headingInstructor1">
 <div class="accordion-body">
 <p>Learners often struggle here, many may not work with financial data
 and concepts so they find the example concepts difficult to get their
@@ -4854,7 +4854,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>The selection can be done by using the labels for both the row
 (“Serbia”) and the column (“gdpPercap_2007”):</p>
@@ -4900,7 +4900,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>No, they do not produce the same output! The output of the first
 statement is:</p>
@@ -4959,7 +4959,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <p>Let’s go through this piece of code line by line.</p>
 <div class="codewrapper sourceCode" id="cb32">
@@ -5041,7 +5041,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>For each column in <code>data</code>, <code>idxmin</code> will return
 the index value corresponding to each column’s minimum;
@@ -5079,7 +5079,7 @@ <h3 class="callout-title">Practice with Selection<a class="anchor" aria-label="a
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>1:</p>
 <div class="codewrapper sourceCode" id="cb38">
@@ -5144,7 +5144,7 @@ <h3 class="callout-title">Many Ways of Access<a class="anchor" aria-label="ancho
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>1. Access a single column:</p>
 <div class="codewrapper sourceCode" id="cb42">
@@ -5330,7 +5330,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <p>Among many choices, <code>dir()</code> lists the
 <code>median()</code> function as a possibility. Thus,</p>
@@ -6208,7 +6208,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb22">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -6243,7 +6243,7 @@ <h3 class="callout-title">How Large is a Slice?<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <p>The list <code>values[start:stop]</code> has up to
 <code>stop - start</code> elements. For example,
@@ -6289,7 +6289,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>
@@ -6340,7 +6340,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <p>The program prints <code>m</code>.</p>
 <ol style="list-style-type: decimal">
@@ -6388,7 +6388,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <p>The program prints</p>
 <div class="codewrapper sourceCode" id="cb27">
@@ -6434,7 +6434,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -6483,7 +6483,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <p>Program A prints</p>
 <div class="codewrapper">
@@ -6542,7 +6542,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <p>Program A prints</p>
 <div class="codewrapper">
@@ -7922,7 +7922,7 @@ <h3 class="callout-title">Key Points<a class="anchor" aria-label="anchor" href="
 </div>
 </section></section><section id="aio-14-looping-data-sets"><p>Content from <a href="14-looping-data-sets.html">Looping Over Data Sets</a></p>
 <hr>
-<p>Last updated on 2023-05-02 |
+<p>Last updated on 2024-03-05 |
         
         <a href="https://github.com/swcarpentry/python-novice-gapminder/edit/main/episodes/14-looping-data-sets.md" class="external-link">Edit this page <i aria-hidden="true" data-feather="edit"></i></a></p>
 <p>Estimated time: <i aria-hidden="true" data-feather="clock"></i> 15 minutes</p>
@@ -8169,7 +8169,10 @@ <h3 class="callout-title">Comparing Data<a class="anchor" aria-label="anchor" hr
 </h3>
 <div class="callout-content">
 <p>Write a program that reads in the regional data sets and plots the
-average GDP per capita for each region over time in a single chart.</p>
+average GDP per capita for each region over time in a single chart.
+Pandas will raise an error if it encounters non-numeric columns in a
+dataframe computation so you may need to either filter out those columns
+or tell pandas to ignore them.</p>
 </div>
 </div>
 </div>
@@ -8196,10 +8199,19 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <span id="cb11-8"><a href="#cb11-8" tabindex="-1"></a>    <span class="co"># we will split the string using the split method and `_` as our separator,</span></span>
 <span id="cb11-9"><a href="#cb11-9" tabindex="-1"></a>    <span class="co"># retrieve the last string in the list that split returns (`&lt;region&gt;.csv`), </span></span>
 <span id="cb11-10"><a href="#cb11-10" tabindex="-1"></a>    <span class="co"># and then remove the `.csv` extension from that string.</span></span>
-<span id="cb11-11"><a href="#cb11-11" tabindex="-1"></a>    region <span class="op">=</span> filename.split(<span class="st">'_'</span>)[<span class="op">-</span><span class="dv">1</span>][:<span class="op">-</span><span class="dv">4</span>] </span>
-<span id="cb11-12"><a href="#cb11-12" tabindex="-1"></a>    dataframe.mean().plot(ax<span class="op">=</span>ax, label<span class="op">=</span>region)</span>
-<span id="cb11-13"><a href="#cb11-13" tabindex="-1"></a>plt.legend()</span>
-<span id="cb11-14"><a href="#cb11-14" tabindex="-1"></a>plt.show()</span></code></pre>
+<span id="cb11-11"><a href="#cb11-11" tabindex="-1"></a>    <span class="co"># </span><span class="al">NOTE</span><span class="co">: the pathlib module covered in the next callout also offers</span></span>
+<span id="cb11-12"><a href="#cb11-12" tabindex="-1"></a>    <span class="co"># convenient abstractions for working with filesystem paths and could solve this as well:</span></span>
+<span id="cb11-13"><a href="#cb11-13" tabindex="-1"></a>    <span class="co"># from pathlib import Path</span></span>
+<span id="cb11-14"><a href="#cb11-14" tabindex="-1"></a>    <span class="co"># region = Path(filename).stem.split('_')[-1]</span></span>
+<span id="cb11-15"><a href="#cb11-15" tabindex="-1"></a>    region <span class="op">=</span> filename.split(<span class="st">'_'</span>)[<span class="op">-</span><span class="dv">1</span>][:<span class="op">-</span><span class="dv">4</span>] </span>
+<span id="cb11-16"><a href="#cb11-16" tabindex="-1"></a>    <span class="co"># pandas raises errors when it encounters non-numeric columns in a dataframe computation</span></span>
+<span id="cb11-17"><a href="#cb11-17" tabindex="-1"></a>    <span class="co"># but we can tell pandas to ignore them with the `numeric_only` parameter</span></span>
+<span id="cb11-18"><a href="#cb11-18" tabindex="-1"></a>    dataframe.mean(numeric_only<span class="op">=</span><span class="va">True</span>).plot(ax<span class="op">=</span>ax, label<span class="op">=</span>region)</span>
+<span id="cb11-19"><a href="#cb11-19" tabindex="-1"></a>    <span class="co"># </span><span class="al">NOTE</span><span class="co">: another way of doing this selects just the columns with gdp in their name using the filter method</span></span>
+<span id="cb11-20"><a href="#cb11-20" tabindex="-1"></a>    <span class="co"># dataframe.filter(like="gdp").mean().plot(ax=ax, label=region)</span></span>
+<span id="cb11-21"><a href="#cb11-21" tabindex="-1"></a></span>
+<span id="cb11-22"><a href="#cb11-22" tabindex="-1"></a>plt.legend()</span>
+<span id="cb11-23"><a href="#cb11-23" tabindex="-1"></a>plt.show()</span></code></pre>
 </div>
 </div>
 </div>
@@ -8234,9 +8246,8 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <span><span class="va">gapminder_gdp_africa</span></span>
 <span><span class="va">.csv</span></span></code></pre>
 </div>
-<p><strong>Hint:</strong> It is possible to check all available
-attributes and methods on the <code>Path</code> object with the
-<code>dir()</code> function!</p>
+<p><strong>Hint:</strong> Check all available attributes and methods on
+the <code>Path</code> object with the <code>dir()</code> function.</p>
 </div>
 </div>
 </div>
@@ -8539,7 +8550,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb16">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8578,7 +8589,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper">
 <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8653,7 +8664,7 @@ <h3 class="code-label">OUTPUT<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li><p>The problem with the example is that the function
@@ -8702,7 +8713,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb25">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8745,7 +8756,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb27">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8809,7 +8820,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li><code>2003/2/1</code></li>
@@ -8897,7 +8908,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb34">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -8979,7 +8990,7 @@ <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"><
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li>The average GDP for Japan across the years reported for the 1980s is
@@ -9088,7 +9099,7 @@ <h3 class="callout-title">Simulating a dynamical system<a class="anchor" aria-la
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution9" aria-expanded="false" aria-controls="collapseSolution9">
   <h4 class="accordion-header" id="headingSolution9">Show me the solution</h4>
 </button>
-<div id="collapseSolution9" class="accordion-collapse collapse" aria-labelledby="headingSolution9" data-bs-parent="#accordionSolution9">
+<div id="collapseSolution9" class="accordion-collapse collapse" data-bs-parent="#accordionSolution9" aria-labelledby="headingSolution9">
 <div class="accordion-body">
 <ol style="list-style-type: decimal">
 <li><div class="codewrapper sourceCode" id="cb43">
diff --git a/md5sum.txt b/md5sum.txt
index 9a92e8fc5..4dcd8144a 100644
--- a/md5sum.txt
+++ b/md5sum.txt
@@ -17,7 +17,7 @@
 "episodes/11-lists.md" "1257daeb542377a3b04c6bec0d0ffee1" "site/built/11-lists.md" "2023-07-24"
 "episodes/12-for-loops.md" "1da6e4e57a25f8d4fd64802c2eb682c4" "site/built/12-for-loops.md" "2023-05-02"
 "episodes/13-conditionals.md" "2739086f688f386c32ce56400c6b27e2" "site/built/13-conditionals.md" "2024-02-16"
-"episodes/14-looping-data-sets.md" "e04f11544d1e5f3ca08ddcf22230a3a3" "site/built/14-looping-data-sets.md" "2023-05-02"
+"episodes/14-looping-data-sets.md" "33bc3751e02186ba42ba35d937b03889" "site/built/14-looping-data-sets.md" "2024-03-05"
 "episodes/15-coffee.md" "062bae79eb17ee57f183b21658a8d813" "site/built/15-coffee.md" "2023-05-02"
 "episodes/16-writing-functions.md" "0f162f45b0072659b0113baf01ade027" "site/built/16-writing-functions.md" "2023-07-24"
 "episodes/17-scope.md" "8109afb18f278a482083d867ad80da6e" "site/built/17-scope.md" "2023-05-02"
diff --git a/pkgdown.yml b/pkgdown.yml
index 5b25dc419..b80e8ff06 100644
--- a/pkgdown.yml
+++ b/pkgdown.yml
@@ -2,5 +2,5 @@ pandoc: 3.1.11
 pkgdown: 2.0.7
 pkgdown_sha: ~
 articles: {}
-last_built: 2024-03-05T00:08Z
+last_built: 2024-03-05T20:55Z