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| author | Mark Dickinson <dickinsm@gmail.com> | 2010-04-03 11:08:14 (GMT) |
|---|---|---|
| committer | Mark Dickinson <dickinsm@gmail.com> | 2010-04-03 11:08:14 (GMT) |
| commit | ac256ab2843dfb6c28af0227202df67664ed462e (patch) | |
| tree | e4b82bd27da37911a04fde01cc06e7ddc39681df /Doc/library/decimal.rst | |
| parent | 5fc16b469ea96f1db11bb2fc9996ac056e8e1c3c (diff) | |
| download | cpython-ac256ab2843dfb6c28af0227202df67664ed462e.zip cpython-ac256ab2843dfb6c28af0227202df67664ed462e.tar.gz cpython-ac256ab2843dfb6c28af0227202df67664ed462e.tar.bz2 | |
Merged revisions 79583,79588-79589 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
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r79583 | mark.dickinson | 2010-04-02 09:53:22 +0100 (Fri, 02 Apr 2010) | 7 lines
Issue #2531: Make float-to-decimal comparisons return correct results.
Float to decimal comparison operations now return a result based on
the numeric values of the operands. Decimal.__hash__ has also been
fixed so that Decimal and float values that compare equal have equal
hash value.
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r79588 | mark.dickinson | 2010-04-02 11:17:07 +0100 (Fri, 02 Apr 2010) | 2 lines
Issue #7279: Make comparisons involving a Decimal sNaN signal InvalidOperation.
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r79589 | mark.dickinson | 2010-04-02 11:35:12 +0100 (Fri, 02 Apr 2010) | 6 lines
Issue #7279: Make Decimal('nan') hashable. Decimal('snan') remains unhashable.
Also rewrite the Decimal __hash__ method so that it doesn't rely on
float('inf') being valid: float('inf') could raise an exception on
platforms not using IEEE 754 arithmetic.
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Diffstat (limited to 'Doc/library/decimal.rst')
| -rw-r--r-- | Doc/library/decimal.rst | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Doc/library/decimal.rst b/Doc/library/decimal.rst index 9d6ad81..8a806e9 100644 --- a/Doc/library/decimal.rst +++ b/Doc/library/decimal.rst @@ -358,6 +358,24 @@ Decimal objects compared, sorted, and coerced to another type (such as :class:`float` or :class:`int`). + Decimal objects cannot generally be combined with floats in + arithmetic operations: an attempt to add a :class:`Decimal` to a + :class:`float`, for example, will raise a :exc:`TypeError`. + There's one exception to this rule: it's possible to use Python's + comparison operators to compare a :class:`float` instance ``x`` + with a :class:`Decimal` instance ``y``. Without this exception, + comparisons between :class:`Decimal` and :class:`float` instances + would follow the general rules for comparing objects of different + types described in the :ref:`expressions` section of the reference + manual, leading to confusing results. + + .. versionchanged:: 2.7 + A comparison between a :class:`float` instance ``x`` and a + :class:`Decimal` instance ``y`` now returns a result based on + the values of ``x`` and ``y``. In earlier versions ``x < y`` + returned the same (arbitrary) result for any :class:`Decimal` + instance ``x`` and any :class:`float` instance ``y``. + In addition to the standard numeric properties, decimal floating point objects also have a number of specialized methods: |