正则表达式字符串以在 Javascript 中不起作用结束 [英] Regex string ends with not working in Javascript

问题描述

我对正则表达式不是很熟悉.我试图测试一个字符串是否以另一个字符串结尾.当我期望为 true 时，下面的代码返回 null.代码有什么问题?

I am not very familiar with regex. I was trying to test if a string ends with another string. The code below returns null when I was expecting true. What's wrong with the code?

var id = "John";
var exists  ="blahJohn".match(/id$/);
alert(exists);

推荐答案

好吧，使用这种方法，您需要使用 RegExp 构造函数，使用 id 变量构建正则表达式:

Well, with this approach, you would need to use the RegExp constructor, to build a regular expression using your id variable:

var id = "John";
var exists = new RegExp(id+"$").test("blahJohn");
alert(exists);

但是有很多方法可以实现，例如，您可以取字符串的最后一个 id.length 字符，并将其与 id 进行比较:

But there are plenty ways to achieve that, for example, you can take the last id.length characters of the string, and compare it with id:

var id = "John";
var exist = "blahJohn".slice(-id.length) == id; // true

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