Python re.sub() 的一个奇怪问题? - V2EX
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zmrenwu

Python re.sub() 的一个奇怪问题?

  •  
  •   zmrenwu Nov 27, 2016 2705 views
    This topic created in 3473 days ago, the information mentioned may be changed or developed.
    >>> def mark(mo): print(mo.group(1)) return mo.group(1) >>> re.sub(r'@(yangxg)|@(zengshao)|@(zmrenwu)', mark, '@yangxg @zengshao @zmrenwu') yangxg None None 

    原本的的意图去掉每个用户名前的 @ 符号,期望的输入应该是:yangxg zengshao zmrenwu

    但事实上对 @zengshao @zmrenwu Match 对象的 group(1) 为 None ?这是怎么回事?

    songkaiape
        1
    songkaiape  
       Nov 28, 2016
    不知道你为什么这么写。。 re.sub(r'@(\w+)', mark, '@yangxg @zengshao @zmrenwu') 这样不就可以了么。后面输出为 None 的原因是因为你三个之间是 3 选 1 吧,匹配其中一个就不会匹配后面的了。
    你可以看看下面这篇文章
    http://www.cnblogs.com/huxi/archive/2010/07/04/1771073.html
    hanbaobao2005
        2
    hanbaobao2005  
       Nov 28, 2016
    如果这样呢?
    for i in ['@yangxg', '@zengshao', '@zmrenwu']:
    re.sub(r'@(yangxg|zengshao|zmrenwu)', mark, i)

    Python 会为每个() 分配 group, 你那种写法应该要判断 group(1), group(2), group(3)
    zmrenwu
        3
    zmrenwu  
    OP
       Nov 28, 2016
    @hanbaobao2005 谢谢,我错误理解了捕获组的含义,更正成这样就可以了: re.sub(r'@(yangxg|zengshao|zmrenwu)', mark, '@yangxg @zengshao @zmrenwu')
    zmrenwu
        4
    zmrenwu  
    OP
       Nov 28, 2016
    @songkaiape 嗯,你的是对的,只是因为我需要匹配特定的用户名,所以我把 (\w+) 改成了 (yangxg|zengshao|zmrenwu)
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