Need a python module for stemming of text documents

Question

I need a good python module for stemming text documents in the pre-processing stage.

I found this one

http://pypi.python.org/pypi/PyStemmer/1.0.1

but i cannot find the documentation int the link provided.

I anyone knows where to find the documentation or any other good stemming algorithm please help.

Answer 1

You may want to try NLTK

>>> from nltk import PorterStemmer
>>> PorterStemmer().stem('complications')

Answer 2

All these stemmers that have been discussed here are algorithmic stemmer,hence they can always produce unexpected results such as

In [3]: from nltk.stem.porter import *

In [4]: stemmer = PorterStemmer()

In [5]: stemmer.stem('identified')
Out[5]: u'identifi'

In [6]: stemmer.stem('nonsensical')
Out[6]: u'nonsens'

To correctly get the root words one need a dictionary based stemmer such as Hunspell Stemmer.Here is a python implementation of it in the following link. Example code is here

>>> import hunspell
>>> hobj = hunspell.HunSpell('/usr/share/myspell/en_US.dic', '/usr/share/myspell/en_US.aff')
>>> hobj.spell('spookie')
False
>>> hobj.suggest('spookie')
['spookier', 'spookiness', 'spooky', 'spook', 'spoonbill']
>>> hobj.spell('spooky')
True
>>> hobj.analyze('linked')
[' st:link fl:D']
>>> hobj.stem('linked')
['link']