[英]How to strip whitespace from before but not after punctuation in python
relative python newbie here. 相对python新手在这里。 I have a text string output from a program I can't modify. 我有一个我无法修改的程序的文本字符串输出。 For discussion lets say: 讨论让我们说:
text = "This text . Is to test . How it works ! Will it! Or won't it ? Hmm ?"
I want to remove the space before the punctuation, but not remove the second space. 我想在标点符号之前删除空格,但不删除第二个空格。 I've been trying to do it with regex, and I know that I can match the instances I want using match='\\s[\\?.!\\"]\\s' as my search term. 我一直试图用正则表达式来做,我知道我可以使用match ='\\ s [\\?。!\\“] \\ s'作为我的搜索词来匹配我想要的实例。
x=re.search('\s[\?\.\!\"]\s',text)
Is there a way with a re.sub to replace the search term with the leading whitespace removed? 是否有一种方法可以使用re.sub替换搜索词并删除前导空格? Any ideas on how to proceed? 关于如何进行的任何想法?
Put a group around the text you want to keep and refer to that group by number in the replacement pattern: 在要保留的文本周围放置一个组,并在替换模式中按编号引用该组:
re.sub(r'\s([?.!"](?:\s|$))', r'\1', text)
Note that I used a r''
raw string to avoid having to use too many backslashes; 请注意,我使用了一个r''
原始字符串,以避免使用太多的反斜杠; you didn't need to add quite so many, however. 但是,你不需要添加那么多。
I also adjusted the match for the following space; 我还调整了以下空间的匹配; it now matches either a space or the end of the string. 它现在匹配一个空格或字符串的结尾。
Demo: 演示:
>>> import re
>>> text = "This text . Is to test . How it works ! Will it! Or won't it ? Hmm ?"
>>> re.sub(r'\s([?.!"](?:\s|$))', r'\1', text)
"This text. Is to test. How it works! Will it! Or won't it? Hmm?"
Use re.sub
instead of re.search
. 使用re.sub
而不是re.search
。
>>> text = "This text . Is to test . How it works ! Will it! Or won't it ? Hmm ?"
>>> re.sub(r'\s+([?.!"])', r'\1', text)
"This text. Is to test. How it works! Will it! Or won't it? Hmm?"
You don't need to escape ?
你不需要逃避?
, .
, .
, !
, !
, "
inside []
becaue special characters lose their meaning inside []
. , "
内部[]
因为特殊字符在[]
内失去意义。
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