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svn+ssh://pythondev@svn.python.org/python/trunk ........ r60701 | georg.brandl | 2008-02-09 22:36:15 +0100 (Sat, 09 Feb 2008) | 2 lines Needs only 2.4 now. ........ r60702 | georg.brandl | 2008-02-09 22:38:54 +0100 (Sat, 09 Feb 2008) | 2 lines Docs are rst now. ........ r60703 | georg.brandl | 2008-02-09 23:00:00 +0100 (Sat, 09 Feb 2008) | 2 lines Fix link. ........ r60704 | georg.brandl | 2008-02-10 00:09:25 +0100 (Sun, 10 Feb 2008) | 2 lines Fix for newest doctools. ........ r60709 | raymond.hettinger | 2008-02-10 08:21:09 +0100 (Sun, 10 Feb 2008) | 1 line Clarify that decimal also supports fixed-point arithmetic. ........ r60710 | nick.coghlan | 2008-02-10 08:32:52 +0100 (Sun, 10 Feb 2008) | 1 line Add missing NEWS entry for r60695 ........ r60712 | mark.dickinson | 2008-02-10 15:58:38 +0100 (Sun, 10 Feb 2008) | 3 lines Turn classmethods into staticmethods, and avoid calling the constructor of subclasses of Rational. (See discussion in issue #1682.) ........ r60715 | mark.dickinson | 2008-02-10 16:19:58 +0100 (Sun, 10 Feb 2008) | 2 lines Typos in decimal comment and documentation ........ r60716 | skip.montanaro | 2008-02-10 16:31:54 +0100 (Sun, 10 Feb 2008) | 2 lines Get the saying right. ;-) ........ r60717 | skip.montanaro | 2008-02-10 16:32:16 +0100 (Sun, 10 Feb 2008) | 2 lines whoops - revert ........ r60718 | mark.dickinson | 2008-02-10 20:23:36 +0100 (Sun, 10 Feb 2008) | 2 lines Remove reference to Rational ........ r60719 | raymond.hettinger | 2008-02-10 21:35:16 +0100 (Sun, 10 Feb 2008) | 1 line Complete an open todo on pickletools -- add a pickle optimizer. ........ r60721 | mark.dickinson | 2008-02-10 22:29:51 +0100 (Sun, 10 Feb 2008) | 3 lines Rename rational.Rational to fractions.Fraction, to avoid name clash with numbers.Rational. See issue #1682 for related discussion. ........ r60722 | christian.heimes | 2008-02-11 03:26:22 +0100 (Mon, 11 Feb 2008) | 1 line The test requires the network resource ........ r60723 | mark.dickinson | 2008-02-11 04:11:55 +0100 (Mon, 11 Feb 2008) | 3 lines Put an extra space into the repr of a Fraction: Fraction(1, 2) instead of Fraction(1,2). ........
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Doc/library/fractions.rst
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Doc/library/fractions.rst
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:mod:`fractions` --- Rational numbers
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====================================
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.. module:: fractions
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:synopsis: Rational numbers.
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.. moduleauthor:: Jeffrey Yasskin <jyasskin at gmail.com>
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.. sectionauthor:: Jeffrey Yasskin <jyasskin at gmail.com>
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.. versionadded:: 2.6
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The :mod:`fractions` module defines an immutable, infinite-precision
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Rational number class.
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.. class:: Fraction(numerator=0, denominator=1)
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Fraction(other_fraction)
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Fraction(string)
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The first version requires that *numerator* and *denominator* are
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instances of :class:`numbers.Integral` and returns a new
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``Fraction`` representing ``numerator/denominator``. If
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*denominator* is :const:`0`, raises a :exc:`ZeroDivisionError`. The
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second version requires that *other_fraction* is an instance of
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:class:`numbers.Fraction` and returns an instance of
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:class:`Rational` with the same value. The third version expects a
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string of the form ``[-+]?[0-9]+(/[0-9]+)?``, optionally surrounded
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by spaces.
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Implements all of the methods and operations from
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:class:`numbers.Rational` and is immutable and hashable.
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.. method:: Fraction.from_float(flt)
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This classmethod constructs a :class:`Fraction` representing the
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exact value of *flt*, which must be a :class:`float`. Beware that
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``Fraction.from_float(0.3)`` is not the same value as ``Rational(3,
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10)``
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.. method:: Fraction.from_decimal(dec)
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This classmethod constructs a :class:`Fraction` representing the
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exact value of *dec*, which must be a
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:class:`decimal.Decimal`.
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.. method:: Fraction.__floor__()
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Returns the greatest :class:`int` ``<= self``. Will be accessible
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through :func:`math.floor` in Py3k.
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.. method:: Fraction.__ceil__()
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Returns the least :class:`int` ``>= self``. Will be accessible
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through :func:`math.ceil` in Py3k.
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.. method:: Fraction.__round__()
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Fraction.__round__(ndigits)
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The first version returns the nearest :class:`int` to ``self``,
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rounding half to even. The second version rounds ``self`` to the
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nearest multiple of ``Fraction(1, 10**ndigits)`` (logically, if
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``ndigits`` is negative), again rounding half toward even. Will be
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accessible through :func:`round` in Py3k.
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.. seealso::
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Module :mod:`numbers`
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The abstract base classes making up the numeric tower.
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