问题
I am using this regex :
Regex.Replace(value.Trim(), @"\s+", " ");
To trim and minimize extra spaces into one space.
The problem is that it also removes new lines from the text.
How can I fix the regex so that it will keep the new lines ?
回答1:
Exclude CRLF's [^\S\r\n]+ within the whitespace class.[^] is a negative class. \S is a negative class which equals not [ space, tab, ff, lf, cr ]
The thing about negative classes is it factored out of the group and applies to each member
in the group separately. And like math two negative equal a positive.
Not Not whitespace = [^\S] = [\s]
However, the negative condition applies to the next class item as well as the next ...
So, now that whitespace is included, you can exclude particular whitespace items from the class.[^\S\r\n] means all whitespace except CR or LF.
回答2:
Haven't managed to test it in C# yet, but the following works on http://www.regexr.com/:
Regex.Replace(value.Trim(), @"[^\S\r\n]+", " ");
Credit goes to Match whitespace but not newlines
The Regex works by matching the negated character class of not-whitespace or return / newlines.
来源：https://stackoverflow.com/questions/25954446/c-sharp-regex-remove-extra-whitespaces-but-keep-new-lines