notes.txt

Chap 4:
Lists, Arrays - vectors & strings , Structures, Hash Tables
Instance.

Make the array:

(make-array
  '(2 3)                    ; Dimensions of the array
  :initial-element nil)     ; Element to be filled by default.

Retrieve an element:
(aref arr 0 0)

setf works the normal way

Literal way to denote arrays is #na where n is the number of dimensions
#2a((b nil nil) (nil nil nil))

If *print-array* is t then an array will always be printed in the above form.

For 1D array
(setf vec (make-array 4 :initial-element nil))
#(nil nil nil nil)

1D Array == Vector

(vector "a" 'b 3)
#("a" B 3)

Use the above syntax to denote a literal vector.

aref can be used, but svref is faster

(svref vec 0)

STRINGS - Are vectors of characters.

constant strings are "series of characters surrounded by double quotes"

individual characters - #\c

char-code & code-char

aref will work on strings, but char is faster

(aref "afroz" 1) OR (char "afroz" 1)

setf works as usual for strings.

Calling format with |nil| as the first argument makes it return as a string what it would have printed.

(format nil "~A or ~A" "truth" "dare")

Sequence includes lists and vectors (and therefore strings)


                  Sequence
                     |
         -----------------------
        |                      |
      array                  list
        |
     vector                  
        |
    strings

Functions Learned:
make-array  -   make the array
aref    -   reference an element of the array
vector  -   make a vector
svref   -   reference an element of the vector
char-code   -   character to number
code-char   -   number to character
char<, char<=, char>, char>=, char/=    -   comparison functions on characters
string-equal    -   ignores case
concatenate -   concatenates 'stuff' (concatenate 'string "not " "to worry")