nltk.tag.sequential

module documentation

(source)

Classes for tagging sentences sequentially, left to right. The abstract base class SequentialBackoffTagger serves as the base class for all the taggers in this module. Tagging of individual words is performed by the method choose_tag(), which is defined by subclasses of SequentialBackoffTagger. If a tagger is unable to determine a tag for the specified token, then its backoff tagger is consulted instead. Any SequentialBackoffTagger may serve as a backoff tagger for any other SequentialBackoffTagger.

Class	`AffixTagger`	A tagger that chooses a token's tag based on a leading or trailing substring of its word string. (It is important to note that these substrings are not necessarily "true" morphological affixes). In particular, a fixed-length substring of the word is looked up in a table, and the corresponding tag is returned...
Class	`BigramTagger`	A tagger that chooses a token's tag based its word string and on the preceding words' tag. In particular, a tuple consisting of the previous tag and the word is looked up in a table, and the corresponding tag is returned.
Class	`ClassifierBasedPOSTagger`	A classifier based part of speech tagger.
Class	`ClassifierBasedTagger`	A sequential tagger that uses a classifier to choose the tag for each token in a sentence. The featureset input for the classifier is generated by a feature detector function:
Class	`ContextTagger`	An abstract base class for sequential backoff taggers that choose a tag for a token based on the value of its "context". Different subclasses are used to define different contexts.
Class	`DefaultTagger`	A tagger that assigns the same tag to every token.
Class	`NgramTagger`	A tagger that chooses a token's tag based on its word string and on the preceding n word's tags. In particular, a tuple (tags[i-n:i-1], words[i]) is looked up in a table, and the corresponding tag is returned...
Class	`RegexpTagger`	Regular Expression Tagger
Class	`SequentialBackoffTagger`	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.
Class	`TrigramTagger`	A tagger that chooses a token's tag based its word string and on the preceding two words' tags. In particular, a tuple consisting of the previous two tags and the word is looked up in a table, and the corresponding tag is returned.
Class	`UnigramTagger`	Unigram Tagger