nltk.collocations.BigramCollocationFinder

class documentation

class BigramCollocationFinder(AbstractCollocationFinder): (source)

Constructor: BigramCollocationFinder(word_fd, bigram_fd, window_size)

View In Hierarchy

A tool for the finding and ranking of bigram collocations or other association measures. It is often useful to use from_words() rather than constructing an instance directly.

Class Method from_words Construct a BigramCollocationFinder for all bigrams in the given sequence. When window_size > 2, count non-contiguous bigrams, in the style of Church and Hanks's (1990) association ratio.
Method __init__ Construct a BigramCollocationFinder, given FreqDists for appearances of words and (possibly non-contiguous) bigrams.
Method score_ngram Returns the score for a given bigram using the given scoring function. Following Church and Hanks (1990), counts are scaled by a factor of 1/(window_size - 1).
Class Variable default_ws Undocumented
Instance Variable window_size Undocumented

Inherited from AbstractCollocationFinder:

Class Method from_documents Constructs a collocation finder given a collection of documents, each of which is a list (or iterable) of tokens.
Method above_score Returns a sequence of ngrams, ordered by decreasing score, whose scores each exceed the given minimum score.
Method apply_freq_filter Removes candidate ngrams which have frequency less than min_freq.
Method apply_ngram_filter Removes candidate ngrams (w1, w2, ...) where fn(w1, w2, ...) evaluates to True.
Method apply_word_filter Removes candidate ngrams (w1, w2, ...) where any of (fn(w1), fn(w2), ...) evaluates to True.
Method nbest Returns the top n ngrams when scored by the given function.
Method score_ngrams Returns a sequence of (ngram, score) pairs ordered from highest to lowest score, as determined by the scoring function provided.
Instance Variable N Undocumented
Instance Variable ngram_fd Undocumented
Instance Variable word_fd Undocumented
Class Method _build_new_documents Pad the document with the place holder according to the window_size
Static Method _ngram_freqdist Undocumented
Method _apply_filter Generic filter removes ngrams from the frequency distribution if the function returns True when passed an ngram tuple.
Method _score_ngrams Generates of (ngram, score) pairs as determined by the scoring function provided.
@classmethod
def from_words(cls, words, window_size=2): (source)

Construct a BigramCollocationFinder for all bigrams in the given sequence. When window_size > 2, count non-contiguous bigrams, in the style of Church and Hanks's (1990) association ratio.

def __init__(self, word_fd, bigram_fd, window_size=2): (source)
overrides nltk.collocations.AbstractCollocationFinder.__init__

Construct a BigramCollocationFinder, given FreqDists for appearances of words and (possibly non-contiguous) bigrams.

def score_ngram(self, score_fn, w1, w2): (source)

Returns the score for a given bigram using the given scoring function. Following Church and Hanks (1990), counts are scaled by a factor of 1/(window_size - 1).

default_ws: int = (source)

Undocumented

window_size = (source)

Undocumented