如何替换数组中的项目? [英] How to replace item in array?

问题描述

此数组的每个项目都是一个数字:

Each item of this array is some number:

var items = Array(523,3452,334,31, ...5346);

如何用新物品代替某些物品?

How to replace some item with a new one?

例如，我们要将3452替换为1010，我们将如何做?

For example, we want to replace 3452 with 1010, how would we do this?

推荐答案

var index = items.indexOf(3452);

if (index !== -1) {
    items[index] = 1010;
}

此外，建议您不要使用构造方法初始化数组.而是使用文字语法:

Also it is recommend you not use the constructor method to initialize your arrays. Instead, use the literal syntax:

var items = [523, 3452, 334, 31, 5346];

如果您要使用简洁的JavaScript，并且想缩短-1比较，也可以使用~运算符:

You can also use the ~ operator if you are into terse JavaScript and want to shorten the -1 comparison:

var index = items.indexOf(3452);

if (~index) {
    items[index] = 1010;
}

有时候，我什至喜欢编写一个contains函数来抽象化此检查并使其更容易理解正在发生的事情.太棒了，这对数组和字符串都适用:

Sometimes I even like to write a contains function to abstract this check and make it easier to understand what's going on. What's awesome is this works on arrays and strings both:

var contains = function (haystack, needle) {
    return !!~haystack.indexOf(needle);
};

// can be used like so now:
if (contains(items, 3452)) {
    // do something else...
}

从针对字符串的ES6/ES2015开始，针对数组的ES2016提出，您可以更轻松地确定源是否包含另一个值:

Starting with ES6/ES2015 for strings, and proposed for ES2016 for arrays, you can more easily determine if a source contains another value:

if (haystack.includes(needle)) {
    // do your thing
}

这篇关于如何替换数组中的项目?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！