Package nltk :: Package tag :: Module sequential :: Class RegexpTagger

YAMLObjectMetaclass RegexpTagger

         object --+        
                  |        
        api.TaggerI --+    
                      |    
SequentialBackoffTagger --+
                          |
             object --+   |
                      |   |
        yaml.YAMLObject --+
                          |
                         RegexpTagger

A tagger that assigns tags to words based on regular expressions over word strings.

Nested Classes

[hide private]

Inherited from yaml.YAMLObject: yaml_dumper, yaml_loader

Instance Methods

[hide private]

__init__(self, regexps, backoff=None)
Construct a new regexp tagger.

source code

str

choose_tag(self, tokens, index, history)
Decide which tag should be used for the specified token, and return that tag.

source code

__repr__(self)

source code

Inherited from SequentialBackoffTagger: tag, tag_one

Inherited from SequentialBackoffTagger (private): _get_backoff

Inherited from api.TaggerI: batch_tag, evaluate

Inherited from api.TaggerI (private): _check_params

Class Methods

[hide private]

Inherited from yaml.YAMLObject: from_yaml, to_yaml

Class Variables

[hide private]

yaml_tag = '!nltk.RegexpTagger'

Inherited from yaml.YAMLObject: yaml_flow_style

Instance Variables

[hide private]

Inherited from SequentialBackoffTagger (private): _taggers

Properties

[hide private]

Inherited from SequentialBackoffTagger: backoff

Method Details

[hide private]

init(self, regexps, backoff=None)
(Constructor)

source code

Construct a new regexp tagger.

Parameters:

regexps (list of (str, str)) - A list of (regexp, tag) pairs, each of which indicates that a word matching regexp should be tagged with tag. The pairs will be evalutated in order. If none of the regexps match a word, then the optional backoff tagger is invoked, else it is assigned the tag None.

Overrides: SequentialBackoffTagger.__init__

choose_tag(self, tokens, index, history)

source code

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 - The list of words that are being tagged.
index - The index of the word whose tag should be returned.
history - A list of the tags for all words before index.

Returns: str

Overrides: SequentialBackoffTagger.choose_tag

(inherited documentation)

repr(self)
(Representation operator)

source code

Overrides: object.__repr__: (inherited documentation)

YAMLObjectMetaclass RegexpTagger

__init__(self, regexps, backoff=None) (Constructor)

choose_tag(self, tokens, index, history)

__repr__(self) (Representation operator)

init(self, regexps, backoff=None)
(Constructor)

repr(self)
(Representation operator)