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Python 3 Text Processing with NLTK 3 Cookbook - Second Edition
book

Python 3 Text Processing with NLTK 3 Cookbook - Second Edition

by Jacob Perkins
August 2014
Beginner to intermediate content levelBeginner to intermediate
304 pages
7h 10m
English
Packt Publishing
Content preview from Python 3 Text Processing with NLTK 3 Cookbook - Second Edition

Training and combining ngram taggers

In addition to UnigramTagger, there are two more NgramTagger subclasses: BigramTagger and TrigramTagger. The BigramTagger subclass uses the previous tag as part of its context, while the TrigramTagger subclass uses the previous two tags. An ngram is a subsequence of n items, so the BigramTagger subclass looks at two items (the previous tagged word and the current word), and the TrigramTagger subclass looks at three items.

These two taggers are good at handling words whose part-of-speech tag is context-dependent. Many words have a different part of speech depending on how they are used. For example, we've been talking about taggers that tag words. In this case, tag is used as a verb. But the result of tagging ...

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Publisher Resources

ISBN: 9781782167853Supplemental Content