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  r61413 | raymond.hettinger | 2008-03-16 06:20:42 +0100 (Sun, 16 Mar 2008) | 1 line

  Update docs to reflect removal of Exact/Inexact
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  r61414 | georg.brandl | 2008-03-16 09:00:19 +0100 (Sun, 16 Mar 2008) | 2 lines

  #2299: typos in newtypes.rst.
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Christian Heimes 2008-03-16 17:29:44 +00:00
parent 0c1f7c0c8a
commit f75b290300
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30
Doc/library/numbers.rst
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@ -6,9 +6,8 @@
The :mod:`numbers` module (:pep:`3141`) defines a hierarchy of numeric abstract
base classes which progressively define more operations. These concepts also
provide a way to distinguish exact from inexact types. None of the types defined
in this module can be instantiated.
base classes which progressively define more operations. None of the types
defined in this module can be instantiated.
.. class:: Number
@ -17,27 +16,6 @@ in this module can be instantiated.
*x* is a number, without caring what kind, use ``isinstance(x, Number)``.
Exact and inexact operations
----------------------------
.. class:: Exact
Subclasses of this type have exact operations.
As long as the result of a homogenous operation is of the same type, you can
assume that it was computed exactly, and there are no round-off errors. Laws
like commutativity and associativity hold.
.. class:: Inexact
Subclasses of this type have inexact operations.
Given X, an instance of :class:`Inexact`, it is possible that ``(X + -X) + 3
== 3``, but ``X + (-X + 3) == 0``. The exact form this error takes will vary
by type, but it's generally unsafe to compare this type for equality.
The numeric tower
-----------------
@ -77,7 +55,7 @@ The numeric tower
.. class:: Rational
Subtypes both :class:`Real` and :class:`Exact`, and adds
Subtypes :class:`Real` and adds
:attr:`Rational.numerator` and :attr:`Rational.denominator` properties, which
should be in lowest terms. With these, it provides a default for
:func:`float`.
@ -237,4 +215,4 @@ forward and reverse instances of any given operator. For example,
__add__, __radd__ = _operator_fallbacks(_add, operator.add)
# ...
# ...