python - 使用 RegEx 使用单词 'but' 对句子进行分块

Question

我正在尝试在单词“但是”(或任何其他并列连词)处使用 RegEx 对句子进行分块。它不起作用...

sentence = nltk.pos_tag(word_tokenize("There are no large collections present but there is spinal canal stenosis."))
result = nltk.RegexpParser(grammar).parse(sentence)
DigDug = nltk.RegexpParser(r'CHUNK: {.*<CC>.*}')
for subtree in DigDug.parse(sentence).subtrees(): 
    if subtree.label() == 'CHUNK': print(subtree.node())

我需要将句子 “There is no large collections present but there is spinal canal stenosis.” 分成两部分:

1. "There are no large collections present"
2. "there is spinal canal stenosis."

我还希望使用相同的代码在“and”和其他并列连词 (CC) 词处拆分句子。但是我的代码不起作用。请帮忙。

Answer 1

我想你可以简单地做

import re
result = re.split(r"\s+(?:but|and)\s+", sentence)

在哪里

`\s`        Match a single character that is a "whitespace character" (spaces, tabs, line breaks, etc.)
`+`         Between one and unlimited times, as many times as possible, giving back as needed (greedy)
`(?:`       Match the regular expression below, do not capture
            Match either the regular expression below (attempting the next alternative only if this one fails)
  `but`     Match the characters "but" literally
  `|`       Or match regular expression number 2 below (the entire group fails if this one fails to match)
  `and`     Match the characters "and" literally
)
`\s`        Match a single character that is a "whitespace character" (spaces, tabs, line breaks, etc.)
`+`         Between one and unlimited times, as many times as possible, giving back as needed (greedy)

您可以在其中添加更多连词，用竖线字符 | 分隔。请注意，这些词不包含在正则表达式中具有特殊含义的字符。如果有疑问，请先使用 re.escape(word)

转义它们