Regexp为什么不匹配? [英] Why doesn't Regexp match?

问题描述

有人可以告诉我为什么这个Regexp不匹配吗?

Can anybody please tell me why doesn't this Regexp match?

var matches = ' @test'.match(new RegExp('(\s+|^)(@|!)(.*?)(\s+|$)', 'g'));

与此匹配:

var matches = '@test'.match(new RegExp('(\s+|^)(@|!)(.*?)(\s+|$)', 'g'));

我已经指定了\s+.那为什么不匹配呢?

I have already specified \s+. Why wouldn't it match it then?

推荐答案

\s不被认为是空格的缩写，因为您是从字符串而不是正则表达式文字构造正则表达式的，而在字符串内部则需要将反斜杠加倍.

\s is not recognized as the whitespace shorthand because you're constructing the regex from a string instead of a regex literal, and inside a string you need to double the backslashes.

所以您需要使用

var matches = ' @test'.match(new RegExp('(\\s+|^)([@!])(.*?)(\\s+|$)', 'g'));

或

var matches = ' @test'.match(/(\s+|^)([@!])(.*?)(\s+|$)/g);

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