text.py 文件源码

def collocations(self, num=20, window_size=2):
        """
        Print collocations derived from the text, ignoring stopwords.

        :seealso: find_collocations
        :param num: The maximum number of collocations to print.
        :type num: int
        :param window_size: The number of tokens spanned by a collocation (default=2)
        :type window_size: int
        """
        if not ('_collocations' in self.__dict__ and self._num == num and self._window_size == window_size):
            self._num = num
            self._window_size = window_size

            #print("Building collocations list")
            from nltk.corpus import stopwords
            ignored_words = stopwords.words('english')
            finder = BigramCollocationFinder.from_words(self.tokens, window_size)
            finder.apply_freq_filter(2)
            finder.apply_word_filter(lambda w: len(w) < 3 or w.lower() in ignored_words)
            bigram_measures = BigramAssocMeasures()
            self._collocations = finder.nbest(bigram_measures.likelihood_ratio, num)
        colloc_strings = [w1+' '+w2 for w1, w2 in self._collocations]
        print(tokenwrap(colloc_strings, separator="; "))