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  r60701 | georg.brandl | 2008-02-09 22:36:15 +0100 (Sat, 09 Feb 2008) | 2 lines

  Needs only 2.4 now.
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  r60702 | georg.brandl | 2008-02-09 22:38:54 +0100 (Sat, 09 Feb 2008) | 2 lines

  Docs are rst now.
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  r60703 | georg.brandl | 2008-02-09 23:00:00 +0100 (Sat, 09 Feb 2008) | 2 lines

  Fix link.
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  r60704 | georg.brandl | 2008-02-10 00:09:25 +0100 (Sun, 10 Feb 2008) | 2 lines

  Fix for newest doctools.
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  r60709 | raymond.hettinger | 2008-02-10 08:21:09 +0100 (Sun, 10 Feb 2008) | 1 line

  Clarify that decimal also supports fixed-point arithmetic.
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  r60710 | nick.coghlan | 2008-02-10 08:32:52 +0100 (Sun, 10 Feb 2008) | 1 line

  Add missing NEWS entry for r60695
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  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.)
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  r60715 | mark.dickinson | 2008-02-10 16:19:58 +0100 (Sun, 10 Feb 2008) | 2 lines

  Typos in decimal comment and documentation
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  r60716 | skip.montanaro | 2008-02-10 16:31:54 +0100 (Sun, 10 Feb 2008) | 2 lines

  Get the saying right. ;-)
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  r60717 | skip.montanaro | 2008-02-10 16:32:16 +0100 (Sun, 10 Feb 2008) | 2 lines

  whoops - revert
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  r60718 | mark.dickinson | 2008-02-10 20:23:36 +0100 (Sun, 10 Feb 2008) | 2 lines

  Remove reference to Rational
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  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.
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  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.
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  r60722 | christian.heimes | 2008-02-11 03:26:22 +0100 (Mon, 11 Feb 2008) | 1 line

  The test requires the network resource
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  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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This commit is contained in:
Christian Heimes 2008-02-11 06:19:17 +00:00
parent ba99c58872
commit 3feef61742
15 changed files with 190 additions and 146 deletions

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:mod:`fractions` --- Rational numbers
====================================
.. module:: fractions
:synopsis: Rational numbers.
.. moduleauthor:: Jeffrey Yasskin <jyasskin at gmail.com>
.. sectionauthor:: Jeffrey Yasskin <jyasskin at gmail.com>
.. versionadded:: 2.6
The :mod:`fractions` module defines an immutable, infinite-precision
Rational number class.
.. class:: Fraction(numerator=0, denominator=1)
Fraction(other_fraction)
Fraction(string)
The first version requires that *numerator* and *denominator* are
instances of :class:`numbers.Integral` and returns a new
``Fraction`` representing ``numerator/denominator``. If
*denominator* is :const:`0`, raises a :exc:`ZeroDivisionError`. The
second version requires that *other_fraction* is an instance of
:class:`numbers.Fraction` and returns an instance of
:class:`Rational` with the same value. The third version expects a
string of the form ``[-+]?[0-9]+(/[0-9]+)?``, optionally surrounded
by spaces.
Implements all of the methods and operations from
:class:`numbers.Rational` and is immutable and hashable.
.. method:: Fraction.from_float(flt)
This classmethod constructs a :class:`Fraction` representing the
exact value of *flt*, which must be a :class:`float`. Beware that
``Fraction.from_float(0.3)`` is not the same value as ``Rational(3,
10)``
.. method:: Fraction.from_decimal(dec)
This classmethod constructs a :class:`Fraction` representing the
exact value of *dec*, which must be a
:class:`decimal.Decimal`.
.. method:: Fraction.__floor__()
Returns the greatest :class:`int` ``<= self``. Will be accessible
through :func:`math.floor` in Py3k.
.. method:: Fraction.__ceil__()
Returns the least :class:`int` ``>= self``. Will be accessible
through :func:`math.ceil` in Py3k.
.. method:: Fraction.__round__()
Fraction.__round__(ndigits)
The first version returns the nearest :class:`int` to ``self``,
rounding half to even. The second version rounds ``self`` to the
nearest multiple of ``Fraction(1, 10**ndigits)`` (logically, if
``ndigits`` is negative), again rounding half toward even. Will be
accessible through :func:`round` in Py3k.
.. seealso::
Module :mod:`numbers`
The abstract base classes making up the numeric tower.