This library is obsolete! Python 3.5's collections.OrderedDict was rewritten in C_, and is now significantly faster than cyordereddict.OrderedDict for almost all operations.

.. _rewritten in C: https://bugs.python.org/issue16991

=============
cyordereddict

.. image:: https://travis-ci.org/shoyer/cyordereddict.svg?branch=master :target: https://travis-ci.org/shoyer/cyordereddict

.. image:: https://badge.fury.io/py/cyordereddict.svg :target: https://pypi.python.org/pypi/cyordereddict

The Python standard library's OrderedDict ported to Cython. A drop-in replacement that is 2-6x faster.

Install: pip install cyordereddict

Dependencies: CPython (2.6, 2.7, 3.3 or 3.4) and a C compiler. Cython is only required for the dev version.

Use: .. code-block:: python

    from cyordereddict import OrderedDict

Benchmarks: Python 2.7:

==================  =================================  =========================
Test                Code                                 Ratio (stdlib / cython)
==================  =================================  =========================
``__init__`` empty  ``OrderedDict()``                                        1.8
``__init__`` list   ``OrderedDict(list_data)``                               4.8
``__init__`` dict   ``OrderedDict(dict_data)``                               4.6
``__setitem__``     ``ordereddict[0] = 0``                                   8.6
``__getitem__``     ``ordereddict[0]``                                       3
``update``          ``ordereddict.update(dict_data)``                        5.5
``__iter__``        ``list(ordereddict)``                                    5.6
``items``           ``ordereddict.items()``                                  5.9
``__contains__``    ``0 in ordereddict``                                     2.3
==================  =================================  =========================

Python 3.4:

==================  =================================  =========================
Test                Code                                 Ratio (stdlib / cython)
==================  =================================  =========================
``__init__`` empty  ``OrderedDict()``                                        1.5
``__init__`` list   ``OrderedDict(list_data)``                               3.9
``__init__`` dict   ``OrderedDict(dict_data)``                               4.2
``__setitem__``     ``ordereddict[0] = 0``                                   8.4
``__getitem__``     ``ordereddict[0]``                                       2.9
``update``          ``ordereddict.update(dict_data)``                        6.5
``__iter__``        ``list(ordereddict)``                                    2.3
``items``           ``list(ordereddict.items())``                            2.1
``__contains__``    ``0 in ordereddict``                                     2.3
==================  =================================  =========================
To run these yourself, use ``cyordereddict.benchmark()``

Cavaets: cyorderedddict.OrderedDict is an extension type (similar to the built-in dict) instead of a Python class. This is necessary for speed, but means that in a few pathological cases its behavior will differ from collections.OrderedDict:

* The ``inspect`` module does not work on ``cyorderedddict.OrderedDict``
  methods.
* Extension types use slots instead of dictionaries, so you cannot add
  custom attributes without making a subclass (e.g.,
  ``OrderedDict.foo = 'bar'`` will fail).

You can do anything else you might do with an OrderedDict, including
subclassing: everything else passes the ``collections.OrderedDict`` test
suite. We based the Cython code directly on the Python standard library,
and thus use separate code bases for Python 2 and 3, specifically to
reduce the potential for introducing new bugs or performance regressions.

License: MIT. Based on the Python standard library, which is under the Python Software Foundation License.