nltk.tag.sequential.DefaultTagger

class documentation

class DefaultTagger(SequentialBackoffTagger): (source)

Constructor: DefaultTagger(tag)

A tagger that assigns the same tag to every token.

>>> from nltk.tag import DefaultTagger
>>> default_tagger = DefaultTagger('NN')
>>> list(default_tagger.tag('This is a test'.split()))
[('This', 'NN'), ('is', 'NN'), ('a', 'NN'), ('test', 'NN')]

This tagger is recommended as a backoff tagger, in cases where a more powerful tagger is unable to assign a tag to the word (e.g. because the word was not seen during training).

Parameters
tag	The tag to assign to each token

Class Method	`decode_json_obj`	Undocumented
Method	`__init__`	Undocumented
Method	`__repr__`	Undocumented
Method	`choose_tag`	Decide which tag should be used for the specified token, and return that tag. If this tagger is unable to determine a tag for the specified token, return None -- do not consult the backoff tagger. This method should be overridden by subclasses of SequentialBackoffTagger.
Method	`encode_json_obj`	Undocumented
Class Variable	`json_tag`	Undocumented
Instance Variable	`_tag`	Undocumented

Inherited from SequentialBackoffTagger:

Method	`tag_one`	Determine an appropriate tag for the specified token, and return that tag. If this tagger is unable to determine a tag for the specified token, then its backoff tagger is consulted.
Property	`backoff`	The backoff tagger for this tagger.
Instance Variable	`_taggers`	A list of all the taggers that should be tried to tag a token (i.e., self and its backoff taggers).

Inherited from TaggerI (via SequentialBackoffTagger):

Method	`evaluate`	Score the accuracy of the tagger against the gold standard. Strip the tags from the gold standard text, retag it using the tagger, then compute the accuracy score.
Method	`tag_sents`	Apply `self.tag()` to each element of sentences. I.e.:
Method	`_check_params`	Undocumented

@classmethod
def decode_json_obj(cls, obj): (source) ¶

Undocumented

def __init__(self, tag): (source) ¶

overrides nltk.tag.sequential.SequentialBackoffTagger.__init__

Undocumented

def __repr__(self): (source) ¶

Undocumented

def choose_tag(self, tokens, index, history): (source) ¶

overrides nltk.tag.sequential.SequentialBackoffTagger.choose_tag

Decide which tag should be used for the specified token, and return that tag. If this tagger is unable to determine a tag for the specified token, return None -- do not consult the backoff tagger. This method should be overridden by subclasses of SequentialBackoffTagger.

Parameters
tokens:list	The list of words that are being tagged.
index:int	The index of the word whose tag should be returned.
history:list(str)	A list of the tags for all words before index.
Returns
str	Undocumented

def encode_json_obj(self): (source) ¶

Undocumented

json_tag: str = (source) ¶

Undocumented

_tag = (source) ¶

Undocumented