如何使用Python nltk.tokenize将包含停用词的短语视为单个标记

时间:2019-04-15 18:12:56

标签: python nltk tokenize stop-words

可以使用nltk.tokenize删除一些不必要的停用词来标记字符串。但是,如何在删除其他停用词的同时将包含停用词的短语标记为单个令牌呢?

例如:

信息输入:特朗普是美国总统。

输出:['特朗普','美国总统']

如何获得仅删除“ is”和第一个“ the”但不删除“ of”和第二个“ the”的结果?

1 个答案:

答案 0 :(得分:2)

您可以使用nltk的Multi-Word Expression Tokenizer,它可以将多单词表达式合并为单个标记。您可以创建包含多词表达式的词典,并向其添加条目,如下所示:

from nltk.tokenize import MWETokenizer
mwetokenizer = MWETokenizer([('President','of','the','United','States')], separator=' ')
mwetokenizer.add_mwe(('President','of','France'))

请注意,MWETokenizer将带标记文本的列表作为输入,然后对其进行重新标记。因此,首先标记该句子。 word_tokenize(),然后将其输入MWETokenizer:

from nltk.tokenize import word_tokenize
sentence = "Trump is the President of the United States, and Macron is the President of France."
mwetokenized_sentence = mwetokenizer.tokenize(word_tokenize(sentence))
# ['Trump', 'is', 'the', 'President of the United States', ',', 'and', 'Macron', 'is', 'the', 'President of France', '.']

然后,过滤掉停用词以获得最终的过滤后的标记化句子:

from nltk.corpus import stopwords
stop_words = set(stopwords.words('english'))
filtered_sentence = [token for token in mwetokenizer.tokenize(word_tokenize(sentence)) if token not in stop_words]
print(filtered_sentence)

输出:

['Trump', 'President of the United States', ',', 'Macron', 'President of France', '.']