negation_detection.py 文件源码

def _lemma_(token):

    if isinstance(token, str):
        return _stem_(token)
    if isinstance(token, unicode):
        return _stem_(token)
    from nltk.corpus import wordnet

    def get_wordnet_pos(treebank_tag):

        if treebank_tag.startswith('J'):
            return wordnet.ADJ
        elif treebank_tag.startswith('V'):
            return wordnet.VERB
        elif treebank_tag.startswith('N'):
            return wordnet.NOUN
        elif treebank_tag.startswith('R'):
            return wordnet.ADV
        else:
            return ''

    from nltk.stem import WordNetLemmatizer
    wordnet_lemmatizer = WordNetLemmatizer()
    p = get_wordnet_pos(token.pos()[0][1])
    if p!=wordnet.VERB:
        return _stem_(token[0])
    rs = wordnet_lemmatizer.lemmatize(token[0], pos=p)
    return rs