Natural Language Processing: Python and NLTK

Looking up lemmas and synonyms in WordNet

Building on the previous recipe, we can also look up lemmas in WordNet to find synonyms of a word. A lemma (in linguistics), is the canonical form or morphological form of a word.

How to do it...

In the following code, we'll find that there are two lemmas for the cookbook Synset using the lemmas() method:

>>> from nltk.corpus import wordnet
>>> syn = wordnet.synsets('cookbook')[0]
>>> lemmas = syn.lemmas()
>>> len(lemmas)
2
>>> lemmas[0].name()
'cookbook'
>>> lemmas[1].name()
'cookery_book'
>>> lemmas[0].synset() == lemmas[1].synset()
True

How it works...

As you can see, cookery_book and cookbook are two distinct lemmas in the same Synset. In fact, a lemma can only belong to a single Synset. In this way, a ...