nltk.SequentialBackoffTagger
¶
-
class
nltk.
SequentialBackoffTagger
(backoff=None)[source]¶ An abstract base class for taggers that tags words sequentially, left to right. Tagging of individual words is performed by the
choose_tag()
method, which should be defined by subclasses. If a tagger is unable to determine a tag for the specified token, then its backoff tagger is consulted.Variables: _taggers – A list of all the taggers that should be tried to tag a token (i.e., self and its backoff taggers).
Methods¶
__init__ ([backoff]) |
|
choose_tag (tokens, index, history) |
Decide which tag should be used for the specified token, and return that tag. |
evaluate (gold) |
Score the accuracy of the tagger against the gold standard. |
tag (tokens) |
|
tag_one (tokens, index, history) |
Determine an appropriate tag for the specified token, and return that tag. |
tag_sents (sentences) |
Apply self.tag() to each element of sentences. |