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pythongh-119189: Fix the power operator for Fraction (pythonGH-119242)
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When using the ** operator or pow() with Fraction as the base
and an exponent that is not rational, a float, or a complex, the
fraction is no longer converted to a float.
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zitterbewegung authored May 31, 2024
1 parent dae0375 commit b9965ef
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Showing 4 changed files with 12 additions and 6 deletions.
4 changes: 3 additions & 1 deletion Lib/fractions.py
Original file line number Diff line number Diff line change
Expand Up @@ -877,8 +877,10 @@ def __pow__(a, b, modulo=None):
# A fractional power will generally produce an
# irrational number.
return float(a) ** float(b)
else:
elif isinstance(b, (float, complex)):
return float(a) ** b
else:
return NotImplemented

def __rpow__(b, a):
"""a ** b"""
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10 changes: 5 additions & 5 deletions Lib/test/test_fractions.py
Original file line number Diff line number Diff line change
Expand Up @@ -925,21 +925,21 @@ def testMixedPower(self):
self.assertTypedEquals(Root(4) ** F(2, 1), Root(4, F(1)))
self.assertTypedEquals(Root(4) ** F(-2, 1), Root(4, -F(1)))
self.assertTypedEquals(Root(4) ** F(-2, 3), Root(4, -3.0))
self.assertEqual(F(3, 2) ** SymbolicReal('X'), SymbolicReal('1.5 ** X'))
self.assertEqual(F(3, 2) ** SymbolicReal('X'), SymbolicReal('3/2 ** X'))
self.assertEqual(SymbolicReal('X') ** F(3, 2), SymbolicReal('X ** 1.5'))

self.assertTypedEquals(F(3, 2) ** Rect(2, 0), Polar(2.25, 0.0))
self.assertTypedEquals(F(1, 1) ** Rect(2, 3), Polar(1.0, 0.0))
self.assertTypedEquals(F(3, 2) ** Rect(2, 0), Polar(F(9,4), 0.0))
self.assertTypedEquals(F(1, 1) ** Rect(2, 3), Polar(F(1), 0.0))
self.assertTypedEquals(F(3, 2) ** RectComplex(2, 0), Polar(2.25, 0.0))
self.assertTypedEquals(F(1, 1) ** RectComplex(2, 3), Polar(1.0, 0.0))
self.assertTypedEquals(Polar(4, 2) ** F(3, 2), Polar(8.0, 3.0))
self.assertTypedEquals(Polar(4, 2) ** F(3, 1), Polar(64, 6))
self.assertTypedEquals(Polar(4, 2) ** F(-3, 1), Polar(0.015625, -6))
self.assertTypedEquals(Polar(4, 2) ** F(-3, 2), Polar(0.125, -3.0))
self.assertEqual(F(3, 2) ** SymbolicComplex('X'), SymbolicComplex('1.5 ** X'))
self.assertEqual(F(3, 2) ** SymbolicComplex('X'), SymbolicComplex('3/2 ** X'))
self.assertEqual(SymbolicComplex('X') ** F(3, 2), SymbolicComplex('X ** 1.5'))

self.assertEqual(F(3, 2) ** Symbolic('X'), Symbolic('1.5 ** X'))
self.assertEqual(F(3, 2) ** Symbolic('X'), Symbolic('3/2 ** X'))
self.assertEqual(Symbolic('X') ** F(3, 2), Symbolic('X ** 1.5'))

def testMixingWithDecimal(self):
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1 change: 1 addition & 0 deletions Misc/ACKS
Original file line number Diff line number Diff line change
Expand Up @@ -751,6 +751,7 @@ Kasun Herath
Chris Herborth
Ivan Herman
Jürgen Hermann
Joshua Jay Herman
Gary Herron
Ernie Hershey
Thomas Herve
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
When using the ``**`` operator or :func:`pow` with :class:`~fractions.Fraction`
as the base and an exponent that is not rational, a float, or a complex, the
fraction is no longer converted to a float.

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