Method from_float

Lib/fractions.py:336–347

Converts a finite float to a rational number, exactly. Beware that Fraction.from_float(0.3) != Fraction(3, 10).

(cls, f)

    @classmethod
    def from_float(cls, f):
        """Converts a finite float to a rational number, exactly.

        Beware that Fraction.from_float(0.3) != Fraction(3, 10).

        """
        if isinstance(f, numbers.Integral):
            return cls(f)
        elif not isinstance(f, float):
            raise TypeError("%s.from_float() only takes floats, not %r (%s)" %
                            (cls.__name__, f, type(f).__name__))
        return cls._from_coprime_ints(*f.as_integer_ratio())

    @classmethod
    def from_decimal(cls, dec):