Python nltk 模块，ChunkParserI() 实例源码

def chunker(sent):

#a = [("I","PRP"),("hear","VBP"),("Jerusalem","NNP"),("bells","NNS"),("ringing","VBG")]
#input_sent = " Rockwell said the agreement calls for it to supply 200 addititonal so-called shipsets for the planes."
    input_sent = sent 
    text = nltk.word_tokenize(input_sent)
    a = nltk.pos_tag(text)
    phrases = []

    tup = ()
    '''test_sents = conll2000.chunked_sents('test.txt', chunk_types=['VP'])
    train_sents = conll2000.chunked_sents('train.txt', chunk_types=['VP'])
    test_sents = conll2000.chunked_sents('test.txt', chunk_types=['NP'])'''
    NP_sents = conll2000.chunked_sents('train.txt', chunk_types=['NP'])
    VP_sents = conll2000.chunked_sents('train.txt', chunk_types=['VP'])
    class ChunkParser(nltk.ChunkParserI):
        def __init__(self, train_sents):
            train_data = [[(t,c) for w,t,c in nltk.chunk.tree2conlltags(sent)] for sent in train_sents]
            self.tagger = nltk.TrigramTagger(train_data)
        def parse(self, sentence):
            pos_tags = [pos for (word,pos) in sentence]
            tagged_pos_tags = self.tagger.tag(pos_tags)
            chunktags = [chunktag for (pos, chunktag) in tagged_pos_tags]
            conlltags = [(word, pos, chunktag) for ((word,pos),chunktag) in zip(sentence, chunktags)]
            return nltk.chunk.util.conlltags2tree(conlltags)

    NPChunker = ChunkParser(NP_sents)
    VPChunker = ChunkParser(VP_sents)
    #print (NPChunker.parse("I hear Jerusalem bells ringing"))
    parsed_sent = NPChunker.parse(a)
    for i in parsed_sent:
        if (type(i)!=type(tup)):
            l=[]
            for t in tuple(i):
                l.append(t[0])
            phrases.append({"NP":" ".join(l)})
    parsed_sent = VPChunker.parse(a)
    for i in parsed_sent:
            if (type(i)!=type(tup)):
                l=[]
                for t in tuple(i):
                    l.append(t[0])
                phrases.append({"VP":" ".join(l)})
    return phrases