如何替换 JavaScript 中特定索引处的字符? [英] How do I replace a character at a particular index in JavaScript?

问题描述

我有一个字符串，比如说 Hello world，我需要替换索引 3 处的字符.如何通过指定索引来替换字符?

I have a string, let's say Hello world and I need to replace the char at index 3. How can I replace a char by specifying a index?

var str = "hello world";

我需要类似的东西

str.replaceAt(0,"h");

推荐答案

在 JavaScript 中，字符串是不可变的，这意味着你能做的最好的事情就是用改变的内容创建一个新的字符串并赋值指向它的变量.

In JavaScript, strings are immutable, which means the best you can do is to create a new string with the changed content and assign the variable to point to it.

您需要自己定义 replaceAt() 函数:

You'll need to define the replaceAt() function yourself:

String.prototype.replaceAt = function(index, replacement) {
    return this.substr(0, index) + replacement + this.substr(index + replacement.length);
}

并像这样使用它:

var hello = "Hello World";
alert(hello.replaceAt(2, "!!")); // He!!o World

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