Javascript Regexp 从变量动态生成? [英] Javascript Regexp dynamic generation from variables?

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问题描述

如何将两个正则表达式组合成一个?

比如我有一个长图案和一个小图案,我需要把小图案放在长图案的前面.

var pattern1 = ':(|:=(|:-(';var pattern2 = ':(|:=(|:-(|:(|:=(|:-('str.match('/'+pattern1+'|'+pattern2+'/gi');

这不起作用.当我连接字符串时,所有斜线都消失了.

解决方案

你必须使用 RegExp:

str.match(new RegExp(pattern1+'|'+pattern2, 'gi'));

<小时><块引用>

当我连接字符串时,所有斜线都消失了.

如果您的模式中有反斜杠来转义特殊的正则表达式字符(例如 (),则必须在字符串中使用 两个 反斜杠(因为 是字符串中的转义字符):new RegExp('\(') 将与 /(/.

所以你的模式必须变成:

var pattern1 = ':\(|:=\(|:-\(';var pattern2 = ':\(|:=\(|:-\(|:\(|:=\(|:-\(';

How to construct two regex patterns into one?

For example I have one long pattern and one smaller, I need to put smaller one in front of long one.

var pattern1 = ':(|:=(|:-(';
var pattern2 = ':(|:=(|:-(|:(|:=(|:-('
str.match('/'+pattern1+'|'+pattern2+'/gi');

This doesn't work. When I'm concatenating strings, all slashes are gone.

解决方案

You have to use RegExp:

str.match(new RegExp(pattern1+'|'+pattern2, 'gi'));


When I'm concatenating strings, all slashes are gone.

If you have a backslash in your pattern to escape a special regex character, (like (), you have to use two backslashes in the string (because is the escape character in a string): new RegExp('\(') would be the same as /(/.

So your patterns have to become:

var pattern1 = ':\(|:=\(|:-\(';
var pattern2 = ':\(|:=\(|:-\(|:\(|:=\(|:-\(';

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