在特定索引处插入字符串

javascript string

2022-08-29 23:20:06

如何在另一个字符串的特定索引处插入字符串？

 var txt1 = "foo baz"

假设我想在“foo”之后插入“bar”，我该如何实现呢？

我想到了，但一定有更简单、更直接的路。substring()

答案 1

插入特定索引（而不是在第一个空格字符处）必须使用字符串切片/子字符串：

var txt2 = txt1.slice(0, 3) + "bar" + txt1.slice(3);

答案 2

你可以把自己的原型设计成 String。splice()

聚填充

if (!String.prototype.splice) {
    /**
     * {JSDoc}
     *
     * The splice() method changes the content of a string by removing a range of
     * characters and/or adding new characters.
     *
     * @this {String}
     * @param {number} start Index at which to start changing the string.
     * @param {number} delCount An integer indicating the number of old chars to remove.
     * @param {string} newSubStr The String that is spliced in.
     * @return {string} A new string with the spliced substring.
     */
    String.prototype.splice = function(start, delCount, newSubStr) {
        return this.slice(0, start) + newSubStr + this.slice(start + Math.abs(delCount));
    };
}

例

String.prototype.splice = function(idx, rem, str) {
    return this.slice(0, idx) + str + this.slice(idx + Math.abs(rem));
};

var result = "foo baz".splice(4, 0, "bar ");

document.body.innerHTML = result; // "foo bar baz"

编辑：已对其进行修改以确保其为绝对值。rem