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cachetools
========================================================================
This module provides various memoizing collections and decorators,
including a variant of the Python 3 Standard Library
`functools.lru_cache` function decorator.
.. code-block:: pycon
>>> from cachetools import LRUCache
>>> cache = LRUCache(maxsize=2)
>>> cache['first'] = 1
>>> cache['second'] = 2
>>> cache
LRUCache(OrderedDict([('first', 1), ('second', 2)]), size=2, maxsize=2)
>>> cache['third'] = 3
>>> cache
LRUCache(OrderedDict([('second', 2), ('third', 3)]), size=2, maxsize=2)
>>> cache['second']
2
>>> cache
LRUCache(OrderedDict([('third', 3), ('second', 2)]), size=2, maxsize=2)
>>> cache['fourth'] = 4
>>> cache
LRUCache(OrderedDict([('second', 2), ('fourth', 4)]), size=2, maxsize=2)
For the purpose of this module, a *cache* is a mutable_ mapping_ with
additional attributes ``size`` and ``maxsize``, which hold the current
and maximum size of the cache, and a (possibly static) method
``getsizeof``.
The current size of the cache is the sum of the results of
``getsizeof`` applied to each of the cache's values, i.e. ``cache.size
== sum(map(cache.getsizeof, cache.values()), 0)``. As a special case,
if ``getsizeof`` returns ``1`` irrespective of its argument,
``cache.size == len(cache)``.
When the cache is full, i.e. ``cache.size > cache.maxsize``, the cache
must choose which item(s) to discard based on a suitable `cache
algorithm`_.
This module provides various cache implementations based on different
cache algorithms, as well as decorators for easily memoizing function
and method calls.
Installation
------------------------------------------------------------------------
Install cachetools using pip::
pip install cachetools
Project Resources
------------------------------------------------------------------------
.. image:: http://img.shields.io/pypi/v/cachetools.svg
:target: https://pypi.python.org/pypi/cachetools/
:alt: Latest PyPI version
.. image:: http://img.shields.io/pypi/dm/cachetools.svg
:target: https://pypi.python.org/pypi/cachetools/
:alt: Number of PyPI downloads
- `Documentation`_
- `Issue Tracker`_
- `Source Code`_
- `Change Log`_
License
------------------------------------------------------------------------
Copyright (c) 2014 Thomas Kemmer.
Licensed under the `MIT License`_.
.. _functools.lru_cache: http://docs.python.org/3.4/library/functools.html#functools.lru_cache
.. _mutable: http://docs.python.org/dev/glossary.html#term-mutable
.. _mapping: http://docs.python.org/dev/glossary.html#term-mapping
.. _cache algorithm: http://en.wikipedia.org/wiki/Cache_algorithms
.. _Documentation: http://pythonhosted.org/cachetools/
.. _Source Code: https://github.com/tkem/cachetools/
.. _Issue Tracker: https://github.com/tkem/cachetools/issues/
.. _Change Log: http://raw.github.com/tkem/cachetools/master/Changes
.. _MIT License: http://raw.github.com/tkem/cachetools/master/LICENSE
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