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