我们从Python开源项目中，提取了以下50个代码示例，用于说明如何使用numbers.Rational()。
def __pow__(a, b): """a ** b If b is not an integer, the result will be a float or complex since roots are generally irrational. If b is an integer, the result will be rational. """ if isinstance(b, Rational): if b.denominator == 1: power = b.numerator if power >= 0: return Fraction(a._numerator ** power, a._denominator ** power) else: return Fraction(a._denominator ** -power, a._numerator ** -power) else: # A fractional power will generally produce an # irrational number. return float(a) ** float(b) else: return float(a) ** b
def __eq__(a, b): """a == b""" if isinstance(b, Rational): return (a._numerator == b.numerator and a._denominator == b.denominator) if isinstance(b, numbers.Complex) and b.imag == 0: b = b.real if isinstance(b, float): if math.isnan(b) or math.isinf(b): # comparisons with an infinity or nan should behave in # the same way for any finite a, so treat a as zero. return 0.0 == b else: return a == a.from_float(b) else: # Since a doesn't know how to compare with b, let's give b # a chance to compare itself with a. return NotImplemented
def _convert_for_comparison(self, other, equality_op=False): if isinstance(other, Decimal): return self, other if isinstance(other, _numbers.Rational): if not self._is_special: self = _dec_from_triple(self._sign, str(int(self._int) * other.denominator), self._exp) return self, Decimal(other.numerator) if equality_op and isinstance(other, _numbers.Complex) and other.imag == 0: other = other.real if isinstance(other, float): context = getcontext() if equality_op: context.flags[FloatOperation] = 1 else: context._raise_error(FloatOperation, "strict semantics for mixing floats and Decimals are enabled") return self, Decimal.from_float(other) return NotImplemented, NotImplemented
def __pow__(a, b): """a ** b If b is not an integer, the result will be a float or complex since roots are generally irrational. If b is an integer, the result will be rational. """ if isinstance(b, numbers.Rational): if b.denominator == 1: power = b.numerator if power >= 0: return Fraction(a._numerator ** power, a._denominator ** power) else: return Fraction(a._denominator ** -power, a._numerator ** -power) else: # A fractional power will generally produce an # irrational number. return float(a) ** float(b) else: return float(a) ** b
def _richcmp(self, other, op): """Helper for comparison operators, for internal use only. Implement comparison between a Rational instance `self`, and either another Rational instance or a float `other`. If `other` is not a Rational instance or a float, return NotImplemented. `op` should be one of the six standard comparison operators. """ # convert other to a Rational instance where reasonable. if isinstance(other, numbers.Rational): return op(self._numerator * other.denominator, self._denominator * other.numerator) if isinstance(other, float): if math.isnan(other) or math.isinf(other): return op(0.0, other) else: return op(self, self.from_float(other)) else: return NotImplemented
def _richcmp(self, other, op): """Helper for comparison operators, for internal use only. Implement comparison between a Rational instance `self`, and either another Rational instance or a float `other`. If `other` is not a Rational instance or a float, return NotImplemented. `op` should be one of the six standard comparison operators. """ # convert other to a Rational instance where reasonable. if isinstance(other, Rational): return op(self._numerator * other.denominator, self._denominator * other.numerator) # comparisons with complex should raise a TypeError, for consistency # with int<->complex, float<->complex, and complex<->complex comparisons. if isinstance(other, complex): raise TypeError("no ordering relation is defined for complex numbers") if isinstance(other, float): if math.isnan(other) or math.isinf(other): return op(0.0, other) else: return op(self, self.from_float(other)) else: return NotImplemented
def __floordiv__(a, b): """a // b""" # Will be math.floor(a / b) in 3.0. div = a / b if isinstance(div, Rational): # trunc(math.floor(div)) doesn't work if the rational is # more precise than a float because the intermediate # rounding may cross an integer boundary. return div.numerator // div.denominator else: return math.floor(div)
def __rfloordiv__(b, a): """a // b""" # Will be math.floor(a / b) in 3.0. div = a / b if isinstance(div, Rational): # trunc(math.floor(div)) doesn't work if the rational is # more precise than a float because the intermediate # rounding may cross an integer boundary. return div.numerator // div.denominator else: return math.floor(div)
def __rpow__(b, a): """a ** b""" if b._denominator == 1 and b._numerator >= 0: # If a is an int, keep it that way if possible. return a ** b._numerator if isinstance(a, Rational): return Fraction(a.numerator, a.denominator) ** b if b._denominator == 1: return a ** b._numerator return a ** float(b)
def test_floats(self): for t in sctypes['float']: assert_(isinstance(t(), numbers.Real), "{0} is not instance of Real".format(t.__name__)) assert_(issubclass(t, numbers.Real), "{0} is not subclass of Real".format(t.__name__)) assert_(not isinstance(t(), numbers.Rational), "{0} is instance of Rational".format(t.__name__)) assert_(not issubclass(t, numbers.Rational), "{0} is subclass of Rational".format(t.__name__))
def _operator_fallbacks(monomorphic_operator, fallback_operator): def forward(a, b): if isinstance(b, (jsint, Fraction)): return monomorphic_operator(a, b) elif isinstance(b, float): return fallback_operator(float(a), b) elif isinstance(b, complex): return fallback_operator(complex(a), b) else: return NotImplemented forward.__name__ = '__' + fallback_operator.__name__ + '__' forward.__doc__ = monomorphic_operator.__doc__ def reverse(b, a): if isinstance(a, numbers.Rational): # Includes ints. return monomorphic_operator(a, b) elif isinstance(a, numbers.Real): return fallback_operator(float(a), float(b)) elif isinstance(a, numbers.Complex): return fallback_operator(complex(a), complex(b)) else: return NotImplemented reverse.__name__ = '__r' + fallback_operator.__name__ + '__' reverse.__doc__ = monomorphic_operator.__doc__ return forward, reverse
def _convert_for_comparison(self, other, equality_op=False): """Given a Decimal instance self and a Python object other, return a pair (s, o) of Decimal instances such that "s op o" is equivalent to "self op other" for any of the 6 comparison operators "op". """ if isinstance(other, Decimal): return self, other # Comparison with a Rational instance (also includes integers): # self op n/d <=> self*d op n (for n and d integers, d positive). # A NaN or infinity can be left unchanged without affecting the # comparison result. if isinstance(other, _numbers.Rational): if not self._is_special: self = _dec_from_triple(self._sign, str(int(self._int) * other.denominator), self._exp) return self, Decimal(other.numerator) # Comparisons with float and complex types. == and != comparisons # with complex numbers should succeed, returning either True or False # as appropriate. Other comparisons return NotImplemented. if equality_op and isinstance(other, _numbers.Complex) and other.imag == 0: other = other.real if isinstance(other, float): return self, Decimal.from_float(other) return NotImplemented, NotImplemented ##### Setup Specific Contexts ############################################ # The default context prototype used by Context() # Is mutable, so that new contexts can have different default values
def _richcmp(self, other, op): if isinstance(other, numbers.Rational): return op(F.from_float(self.value), other) elif isinstance(other, DummyFloat): return op(self.value, other.value) else: return NotImplemented
def test_float(self): self.assertFalse(issubclass(float, Rational)) self.assertTrue(issubclass(float, Real)) self.assertEqual(7.3, float(7.3).real) self.assertEqual(0, float(7.3).imag) self.assertEqual(7.3, float(7.3).conjugate())
def __rpow__(b, a): """a ** b""" if b._denominator == 1 and b._numerator >= 0: # If a is an int, keep it that way if possible. return a ** b._numerator if isinstance(a, numbers.Rational): return Fraction(a.numerator, a.denominator) ** b if b._denominator == 1: return a ** b._numerator return a ** float(b)
