Code Coverage for nltk.tag.util
Untested Functions
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Partially Tested Functions
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import re
from nltk.internals import deprecated
def str2tuple(s, sep='/'):
"""
Given the string representation of a tagged token, return the
corresponding tuple representation. The rightmost occurence of
C{sep} in C{s} will be used to divide C{s} into a word string and
a tag string. If C{sep} does not occur in C{s}, return
C{(s, None)}.
@type s: C{str}
@param s: The string representaiton of a tagged token.
@type sep: C{str}
@param sep: The separator string used to separate word strings
from tags.
"""
loc = s.rfind(sep)
if loc >= 0:
return (s[:loc], s[loc+1:].upper())
else:
return (s, None)
def tuple2str(tagged_token, sep='/'):
"""
Given the tuple representation of a tagged token, return the
corresponding string representation. This representation is
formed by concatenating the token's word string, followed by the
separator, followed by the token's tag. (If the tag is None,
then just return the bare word string.)
@type tagged_token: C{(str, str)}
@param tagged_token: The tuple representation of a tagged token.
@type sep: C{str}
@param sep: The separator string used to separate word strings
from tags.
"""
word, tag = tagged_token
if tag is None:
return word
else:
assert sep not in tag, 'tag may not contain sep!'
return '%s%s%s' % (word, sep, tag)
def untag(tagged_sentence):
"""
Given a tagged sentence, return an untagged version of that
sentence. I.e., return a list containing the first element
of each tuple in C{tagged_sentence}.
>>> untag([('John', 'NNP'), ('saw', 'VBD'), ('Mary', 'NNP')]
['John', 'saw', 'mary']
"""
return [w for (w, t) in tagged_sentence]
from nltk import evaluate
def accuracy(tagger, gold):
"""
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.
@type tagger: C{TaggerI}
@param tagger: The tagger being evaluated.
@type gold: C{list} of C{Token}
@param gold: The list of tagged tokens to score the tagger on.
@rtype: C{float}
"""
tagged_sents = tagger.batch_tag([untag(sent) for sent in gold])
gold_tokens = sum(gold, [])
test_tokens = sum(tagged_sents, [])
return evaluate.accuracy(gold_tokens, test_tokens)
@deprecated("Use nltk.tag.str2tuple(s, sep) instead.")
def tag2tuple(s, sep='/'):
return str2tuple(s, sep)
@deprecated("Use [nltk.tag.str2tuple(t, sep) for t in s.split()] instead.")
def string2tags(s, sep='/'):
return [str2tuple(t, sep) for t in s.split()]
@deprecated("Use ' '.join(nltk.tag.tuple2str(w, sep) for w in t) instead.")
def tags2string(t, sep='/'):
return ' '.join(tuple2str(w, sep) for w in t)
@deprecated("Use [nltk.tag.str2tuple(t, sep)[0] for t in s.split()] instead.")
def string2words(s, sep='/'):
return [str2tuple(t, sep)[0] for t in s.split()]