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
python类Rational()的实例源码
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 __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)
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 _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 __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 _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())
