diff options
Diffstat (limited to 'Lib/fractions.py')
| -rw-r--r-- | Lib/fractions.py | 34 |
1 files changed, 5 insertions, 29 deletions
diff --git a/Lib/fractions.py b/Lib/fractions.py index 9aabab3e3b..8330202d70 100644 --- a/Lib/fractions.py +++ b/Lib/fractions.py @@ -81,7 +81,7 @@ class Fraction(numbers.Rational): __slots__ = ('_numerator', '_denominator') # We're immutable, so use __new__ not __init__ - def __new__(cls, numerator=0, denominator=None, _normalize=True): + def __new__(cls, numerator=0, denominator=None, *, _normalize=True): """Constructs a Rational. Takes a string like '3/2' or '1.5', another Rational instance, a @@ -125,17 +125,9 @@ class Fraction(numbers.Rational): self._denominator = numerator.denominator return self - elif isinstance(numerator, float): - # Exact conversion from float - value = Fraction.from_float(numerator) - self._numerator = value._numerator - self._denominator = value._denominator - return self - - elif isinstance(numerator, Decimal): - value = Fraction.from_decimal(numerator) - self._numerator = value._numerator - self._denominator = value._denominator + elif isinstance(numerator, (float, Decimal)): + # Exact conversion + self._numerator, self._denominator = numerator.as_integer_ratio() return self elif isinstance(numerator, str): @@ -210,10 +202,6 @@ class Fraction(numbers.Rational): elif not isinstance(f, float): raise TypeError("%s.from_float() only takes floats, not %r (%s)" % (cls.__name__, f, type(f).__name__)) - if math.isnan(f): - raise ValueError("Cannot convert %r to %s." % (f, cls.__name__)) - if math.isinf(f): - raise OverflowError("Cannot convert %r to %s." % (f, cls.__name__)) return cls(*f.as_integer_ratio()) @classmethod @@ -226,19 +214,7 @@ class Fraction(numbers.Rational): raise TypeError( "%s.from_decimal() only takes Decimals, not %r (%s)" % (cls.__name__, dec, type(dec).__name__)) - if dec.is_infinite(): - raise OverflowError( - "Cannot convert %s to %s." % (dec, cls.__name__)) - if dec.is_nan(): - raise ValueError("Cannot convert %s to %s." % (dec, cls.__name__)) - sign, digits, exp = dec.as_tuple() - digits = int(''.join(map(str, digits))) - if sign: - digits = -digits - if exp >= 0: - return cls(digits * 10 ** exp) - else: - return cls(digits, 10 ** -exp) + return cls(*dec.as_integer_ratio()) def limit_denominator(self, max_denominator=1000000): """Closest Fraction to self with denominator at most max_denominator. |