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natsort
=======
.. image:: https://travis-ci.org/SethMMorton/natsort.svg?branch=master
:target: https://travis-ci.org/SethMMorton/natsort
.. image:: https://coveralls.io/repos/SethMMorton/natsort/badge.png?branch=master
:target: https://coveralls.io/r/SethMMorton/natsort?branch=master
Natural sorting for python.
- Source Code: https://github.com/SethMMorton/natsort
- Downloads: https://pypi.python.org/pypi/natsort
- Documentation: http://pythonhosted.org//natsort/
Quick Description
-----------------
When you try to sort a list of strings that contain numbers, the normal python
sort algorithm sorts lexicographically, so you might not get the results that you
expect::
>>> a = ['a2', 'a9', 'a1', 'a4', 'a10']
>>> sorted(a)
['a1', 'a10', 'a2', 'a4', 'a9']
Notice that it has the order ('1', '10', '2') - this is because the list is
being sorted in lexicographical order, which sorts numbers like you would
letters (i.e. 'b', 'ba', 'c').
``natsort`` provides a function ``natsorted`` that helps sort lists "naturally",
either as real numbers (i.e. signed/unsigned floats or ints), or as versions.
Using ``natsorted`` is simple::
>>> from natsort import natsorted
>>> a = ['a2', 'a9', 'a1', 'a4', 'a10']
>>> natsorted(a)
['a1', 'a2', 'a4', 'a9', 'a10']
``natsorted`` identifies real numbers anywhere in a string and sorts them
naturally.
Sorting version numbers is just as easy with the ``versorted`` function::
>>> from natsort import versorted
>>> a = ['version-1.9', 'version-2.0', 'version-1.11', 'version-1.10']
>>> versorted(a)
['version-1.9', 'version-1.10', 'version-1.11', 'version-2.0']
>>> natsorted(a) # natsorted tries to sort as signed floats, so it won't work
['version-2.0', 'version-1.9', 'version-1.11', 'version-1.10']
You can also perform locale-aware sorting (or "human sorting"), where the
non-numeric characters are ordered based on their meaning, not on their
ordinal value; this can be achieved with the ``humansorted`` function::
>>> a = ['Apple', 'Banana', 'apple', 'banana']
>>> natsorted(a)
['Apple', 'Banana', 'apple', 'banana']
>>> import locale
>>> locale.setlocale(locale.LC_ALL, 'en_US.UTF-8')
'en_US.UTF-8'
>>> from natsort import humansorted
>>> humansorted(a)
['apple', 'Apple', 'banana', 'Banana']
You may find you need to explicitly set the locale to get this to work
(as shown in the example).
Please see the `following caveat <http://pythonhosted.org//natsort/examples.html#bug-note>`_
and the "Optional Dependencies" section
below before using the ``humansorted`` function.
You can mix and match ``int``, ``float``, and ``str`` (or ``unicode``) types
when you sort::
>>> a = ['4.5', 6, 2.0, '5', 'a']
>>> natsorted(a)
[2.0, '4.5', '5', 6, 'a']
>>> # On Python 2, sorted(a) would return [2.0, 6, '4.5', '5', 'a']
>>> # On Python 3, sorted(a) would raise an "unorderable types" TypeError
The natsort algorithm does other fancy things like
- recursively descend into lists of lists
- control the case-sensitivity
- sort file paths correctly
- allow custom sorting keys
- exposes a natsort_key generator to pass to list.sort
Please see the package documentation for more details, including
`examples and recipes <http://pythonhosted.org//natsort/examples.html>`_.
Shell script
------------
``natsort`` comes with a shell script called ``natsort``, or can also be called
from the command line with ``python -m natsort``. The command line script is
only installed onto your ``PATH`` if you don't install via a wheel.
Requirements
------------
``natsort`` requires python version 2.6 or greater
(this includes python 3.x). To run version 2.6, 3.0, or 3.1 the
`argparse <https://pypi.python.org/pypi/argparse>`_ module is required.
Optional Dependencies
---------------------
fastnumbers
'''''''''''
The most efficient sorting can occur if you install the
`fastnumbers <https://pypi.python.org/pypi/fastnumbers>`_ package (it helps
with the string to number conversions.) ``natsort`` will still run (efficiently)
without the package, but if you need to squeeze out that extra juice it is
recommended you include this as a dependency. ``natsort`` will not require (or
check) that `fastnumbers <https://pypi.python.org/pypi/fastnumbers>`_ is installed
at installation.
PyICU
'''''
On some systems, Python's ``locale`` library can be buggy (I have found this to be
the case on Mac OS X), so ``natsort`` will use
`PyICU <https://pypi.python.org/pypi/PyICU>`_ under the hood if it is installed
on your computer; this will give more reliable results. ``natsort`` will not
require (or check) that `PyICU <https://pypi.python.org/pypi/PyICU>`_ is installed
at installation.
Depreciation Notices
--------------------
- In ``natsort`` version 4.0.0, the ``number_type``, ``signed``, ``exp``,
``as_path``, and ``py3_safe`` options will be removed from the (documented)
API, in favor of the ``alg`` option and ``ns`` enum. They will remain as
keyword-only arguments after that (for the foreseeable future).
- In ``natsort`` version 4.0.0, the ``natsort_key`` function will be removed
from the public API. All future development should use ``natsort_keygen``
in preparation for this.
- In ``natsort`` version 3.1.0, the shell script changed how it interpreted
input; previously, all input was assumed to be a filepath, but as of 3.1.0
input is just treated as a string. For most cases the results are the same.
- As of ``natsort`` version 3.4.0, a ``--path`` option has been added to
force the shell script to interpret the input as filepaths.
Author
------
Seth M. Morton
History
-------
These are the last three entries of the changelog. See the package documentation
for the complete `changelog <http://pythonhosted.org//natsort/changelog.html>`_.
09-25-2014 v. 3.5.1
'''''''''''''''''''
- Fixed bug that caused list/tuples to fail when using 'ns.LOWECASEFIRST'
or 'ns.IGNORECASE'.
- Refactored modules so that only the public API was in natsort.py and
ns_enum.py.
- Refactored all import statements to be absolute, not relative.
09-02-2014 v. 3.5.0
'''''''''''''''''''
- Added the 'alg' argument to the 'natsort' functions. This argument
accepts an enum that is used to indicate the options the user wishes
to use. The 'number_type', 'signed', 'exp', 'as_path', and 'py3_safe'
options are being depreciated and will become (undocumented)
keyword-only options in natsort version 4.0.0.
- The user can now modify how 'natsort' handles the case of non-numeric
characters.
- The user can now instruct 'natsort' to use locale-aware sorting, which
allows 'natsort' to perform true "human sorting".
- The `humansorted` convenience function has been included to make this
easier.
- Updated shell script with locale functionality.
08-12-2014 v. 3.4.1
'''''''''''''''''''
- 'natsort' will now use the 'fastnumbers' module if it is installed. This
gives up to an extra 30% boost in speed over the previous performance
enhancements.
- Made documentation point to more 'natsort' resources, and also added a
new example in the examples section.
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