Sample usage for tag

Regression Tests

Sequential Taggers

Add tests for:
  • make sure backoff is being done correctly.

  • make sure ngram taggers don’t use previous sentences for context.

  • make sure ngram taggers see ‘beginning of the sentence’ as a unique context

  • make sure regexp tagger’s regexps are tried in order

  • train on some simple examples, & make sure that the size & the generated models are correct.

  • make sure cutoff works as intended

  • make sure that ngram models only exclude contexts covered by the backoff tagger if the backoff tagger gets that context correct at all locations.

Regression Testing for issue #1025

We want to ensure that a RegexpTagger can be created with more than 100 patterns and does not fail with:

“AssertionError: sorry, but this version only supports 100 named groups”

>>> from nltk.tag import RegexpTagger
>>> patterns = [(str(i), 'NNP',) for i in range(200)]
>>> tagger = RegexpTagger(patterns)

Regression Testing for issue #2483

Ensure that tagging with pos_tag (PerceptronTagger) does not throw an IndexError when attempting tagging an empty string. What it must return instead is not strictly defined.

>>> from nltk.tag import pos_tag
>>> pos_tag(['', 'is', 'a', 'beautiful', 'day'])