如何使用正則表達式在單詞邊界處分割？

Question

我試圖做到這一點：

import re 
sentence = "How are you?" 
print(re.split(r'\b', sentence)) 

結果是

[u'How are you?'] 

我想是這樣[u'How', u'are', u'you', u'?']。這怎麼能實現？

Answer 1

不幸的是，Python無法通過空字符串拆分。

要解決此問題，您需要使用findall而不是split。其實\b只是字的邊界。

它相當於(?<=\w)(?=\W)|(?<=\W)(?=\w)。

這意味着，下面的代碼將工作：

import re 
sentence = "How are you?" 
print(re.findall(r'\w+|\W+', sentence)) 

Answer 2

import re 
split = re.findall(r"[\w']+|[.,!?;]", "How are you?") 
print(split) 

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輸出：

['How', 'are', 'you', '?'] 

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Ideone Demo

Regex101 Demo

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Regex的說明：

"[\w']+|[.,!?;]" 

    1st Alternative: [\w']+ 
     [\w']+ match a single character present in the list below 
      Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed [greedy] 
      \w match any word character [a-zA-Z0-9_] 
      ' the literal character ' 
    2nd Alternative: [.,!?;] 
     [.,!?;] match a single character present in the list below 
      .,!?; a single character in the list .,!?; literally