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author | Steve Dower <steve.dower@microsoft.com> | 2017-02-06 14:12:19 -0800 |
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committer | Steve Dower <steve.dower@microsoft.com> | 2017-02-06 14:12:19 -0800 |
commit | 5b4df5813c20fe96f117d0201965b52e86a1a66d (patch) | |
tree | d991f61bc824ca1b1b92bf7fb16fe3dacd4b1335 /Lib/_pydecimal.py | |
parent | 3e0bdff8a0793d305b972f4a653e4698d440b3ae (diff) | |
parent | 95b272b4e0d5438a12702e51e05d03f5a5a8e505 (diff) | |
download | cpython-5b4df5813c20fe96f117d0201965b52e86a1a66d.tar.gz |
Includes ensurepip and venv packages in nuget package.
Diffstat (limited to 'Lib/_pydecimal.py')
-rw-r--r-- | Lib/_pydecimal.py | 62 |
1 files changed, 56 insertions, 6 deletions
diff --git a/Lib/_pydecimal.py b/Lib/_pydecimal.py index a5ea340e9d..0b40928ff8 100644 --- a/Lib/_pydecimal.py +++ b/Lib/_pydecimal.py @@ -148,7 +148,7 @@ __xname__ = __name__ # sys.modules lookup (--without-threads) __name__ = 'decimal' # For pickling __version__ = '1.70' # Highest version of the spec this complies with # See http://speleotrove.com/decimal/ -__libmpdec_version__ = "2.4.1" # compatible libmpdec version +__libmpdec_version__ = "2.4.2" # compatible libmpdec version import math as _math import numbers as _numbers @@ -589,7 +589,7 @@ class Decimal(object): # From a string # REs insist on real strings, so we can too. if isinstance(value, str): - m = _parser(value.strip()) + m = _parser(value.strip().replace("_", "")) if m is None: if context is None: context = getcontext() @@ -1010,6 +1010,56 @@ class Decimal(object): """ return DecimalTuple(self._sign, tuple(map(int, self._int)), self._exp) + def as_integer_ratio(self): + """Express a finite Decimal instance in the form n / d. + + Returns a pair (n, d) of integers. When called on an infinity + or NaN, raises OverflowError or ValueError respectively. + + >>> Decimal('3.14').as_integer_ratio() + (157, 50) + >>> Decimal('-123e5').as_integer_ratio() + (-12300000, 1) + >>> Decimal('0.00').as_integer_ratio() + (0, 1) + + """ + if self._is_special: + if self.is_nan(): + raise ValueError("cannot convert NaN to integer ratio") + else: + raise OverflowError("cannot convert Infinity to integer ratio") + + if not self: + return 0, 1 + + # Find n, d in lowest terms such that abs(self) == n / d; + # we'll deal with the sign later. + n = int(self._int) + if self._exp >= 0: + # self is an integer. + n, d = n * 10**self._exp, 1 + else: + # Find d2, d5 such that abs(self) = n / (2**d2 * 5**d5). + d5 = -self._exp + while d5 > 0 and n % 5 == 0: + n //= 5 + d5 -= 1 + + # (n & -n).bit_length() - 1 counts trailing zeros in binary + # representation of n (provided n is nonzero). + d2 = -self._exp + shift2 = min((n & -n).bit_length() - 1, d2) + if shift2: + n >>= shift2 + d2 -= shift2 + + d = 5**d5 << d2 + + if self._sign: + n = -n + return n, d + def __repr__(self): """Represents the number as an instance of Decimal.""" # Invariant: eval(repr(d)) == d @@ -4075,7 +4125,7 @@ class Context(object): This will make it round up for that operation. """ rounding = self.rounding - self.rounding= type + self.rounding = type return rounding def create_decimal(self, num='0'): @@ -4084,10 +4134,10 @@ class Context(object): This method implements the to-number operation of the IBM Decimal specification.""" - if isinstance(num, str) and num != num.strip(): + if isinstance(num, str) and (num != num.strip() or '_' in num): return self._raise_error(ConversionSyntax, - "no trailing or leading whitespace is " - "permitted.") + "trailing or leading whitespace and " + "underscores are not permitted.") d = Decimal(num, context=self) if d._isnan() and len(d._int) > self.prec - self.clamp: |