NLTK将标记化句子转换为synset格式

Question

我希望使用NLTK获得单个单词和句子中每个单词之间的相似性.

NLTK可以获得两个特定单词之间的相似性,如下所示.这个方法要求给出对该单词的特定引用,在这种情况下它是'dog.n.01',其中dog是名词,我们想要使用第一个(01)NLTK定义.

dog = wordnet.synset('dog.n.01')
cat = wordnet.synset('cat.n.01')
print  dog.path_similarity(cat)
>> 0.2

问题是我需要从句子中的每个单词中获取词性信息.NLTK包能够获得句子中每个单词的词性,如下所示.但是,这些语音部分('NN','VB','PRP'...)与synset用作参数的格式不匹配.

text = word_tokenize("They refuse to permit us to obtain the refuse permit")
pos_tag(text)
>> [('They', 'PRP'), ('refuse', 'VBP'), ('to', 'TO'), ('permit', 'VB'), ('us', 'PRP'), ('to', 'TO'), ('obtain', 'VB'), ('the', 'DT'), ('refuse', 'NN'), ('permit', 'NN')]

是否可以从pos_tag()获取synset格式的数据导致NLTK？通过synset格式化我的意思是格式dog.n.01

Answer 1

您可以使用简单的转换功能:

from nltk.corpus import wordnet as wn

def penn_to_wn(tag):
    if tag.startswith('J'):
        return wn.ADJ
    elif tag.startswith('N'):
        return wn.NOUN
    elif tag.startswith('R'):
        return wn.ADV
    elif tag.startswith('V'):
        return wn.VERB
    return None

标记句子后,您可以使用此函数将句子中的单词与SYNSET绑定.这是一个例子:

from nltk.stem import WordNetLemmatizer
from nltk import pos_tag, word_tokenize

sentence = "I am going to buy some gifts"
tagged = pos_tag(word_tokenize(sentence))

synsets = []
lemmatzr = WordNetLemmatizer()

for token in tagged:
    wn_tag = penn_to_wn(token[1])
    if not wn_tag:
        continue

    lemma = lemmatzr.lemmatize(token[0], pos=wn_tag)
    synsets.append(wn.synsets(lemma, pos=wn_tag)[0])

print synsets

结果:[Synset('be.v.01'),Synset('travel.v.01'),Synset('buy.v.01'),Synset('gift.n.01')]