JavaScript 正则表达式模式与变量连接
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JavaScript regex pattern concatenate with variable
提问by Komang
How to create regex pattern which is concatenate with variable, something like this:
如何创建与变量连接的正则表达式模式，如下所示：
var test ="52";
var re = new RegExp("/\b"+test+"\b/");
alert('51,52,53'.match(re));
Thanks
谢谢
回答by bobince
var re = new RegExp("/\b"+test+"\b/");
\bin a string literal is a backspace character. When putting a regex in a string literal you need one more round of escaping:
\b在字符串文字中是一个退格字符。将正则表达式放入字符串文字时，您需要再进行一轮转义：
var re = new RegExp("\b"+test+"\b");
(You also don't need the //in this context.)
（//在这种情况下您也不需要。）
回答by Lauri
you can use
您可以使用
/(^|,)52(,|$)/.test('51,52,53')
but i suggest to use
但我建议使用
var list = '51,52,53';
function test2(list, test){
return !((","+list+",").indexOf(","+test+",") === -1)
}
alert( test2(list,52) )
回答by Tapirboy
With ES2015 (aka ES6) you can use template literalswhen constructing RegExp:
使用 ES2015（又名 ES6），您可以在构造RegExp时使用模板文字：
let test = '53'
const regexp = new RegExp(`\b${test}\b`, 'gi') // showing how to pass optional flags
console.log('51, 52, 53, 54'.match(regexp))
// prints array of ['53']
