Issue 9829: Unexpected Fraction.from_float() Behavior (original) (raw)

The Fractions.from_float() call returns an incorrect value when run on certain numbers. Some test runs have been listed below. Note that this problem does not exist when the same float is converted to a string and then passed to the standard Fraction() constructor; I do not know if this is an inherent problem due to the structure of the float itself or an implementation issue.

for x in [1.23, 1.24, 1.25, 1.26, 1.27]: print(Fraction.from_float(x)) print(Fraction(str(x)))

2769713770832855/2251799813685248 123/100 5584463537939415/4503599627370496 31/25 5/4 5/4 5674535530486825/4503599627370496 63/50 2859785763380265/2251799813685248 127/100

The problem does not exist if a string literal is passed either:

print(Fraction('1.23')) 123/100