问题描述
找出 JavaScript 数组是否包含值的最简洁有效的方法是什么?
What is the most concise and efficient way to find out if a JavaScript array contains a value?
这是我知道的唯一方法:
This is the only way I know to do it:
function contains(a, obj) {
for (var i = 0; i < a.length; i++) {
if (a[i] === obj) {
return true;
}
}
return false;
}
有没有更好、更简洁的方法来实现这一点?
Is there a better and more concise way to accomplish this?
推荐答案
现代浏览器有 Array#includes
,它完全和得到广泛支持 IE 除外:
Modern browsers have Array#includes
, which does exactly that and is widely supported by everyone except IE:
console.log(['joe', 'jane', 'mary'].includes('jane')); //true
您也可以使用 Array#indexOf
,它不太直接,但不需要为过时的浏览器提供 polyfill.
You can also use Array#indexOf
, which is less direct, but doesn't require polyfills for outdated browsers.
console.log(['joe', 'jane', 'mary'].indexOf('jane') >= 0); //true
许多框架也提供了类似的方法:
Many frameworks also offer similar methods:
- jQuery:
$.inArray(value, array, [fromIndex])
- Underscore.js:
_.contains(array, value)
(也别名为_.include
和_.includes
) - Dojo 工具包:
dojo.indexOf(array, value, [fromIndex, findLast])
- 原型:
array.indexOf(value)
一个> - MooTools:
array.indexOf(value)
- MochiKit:
findValue(array, value)
- MS Ajax:
array.indexOf(value)代码>
- Ext:
Ext.Array.contains(array, value)
- Lodash:
_.includes(array, value, [from])
(是_.contains
之前的 4.0.0) - Ramda:
R.includes(value, array)
莉>
- jQuery:
$.inArray(value, array, [fromIndex])
- Underscore.js:
_.contains(array, value)
(also aliased as_.include
and_.includes
) - Dojo Toolkit:
dojo.indexOf(array, value, [fromIndex, findLast])
- Prototype:
array.indexOf(value)
- MooTools:
array.indexOf(value)
- MochiKit:
findValue(array, value)
- MS Ajax:
array.indexOf(value)
- Ext:
Ext.Array.contains(array, value)
- Lodash:
_.includes(array, value, [from])
(is_.contains
prior 4.0.0) - Ramda:
R.includes(value, array)
请注意,一些框架将其实现为一个函数,而另一些框架则将该函数添加到数组原型中.
Notice that some frameworks implement this as a function, while others add the function to the array prototype.
这篇关于如何检查数组是否包含 JavaScript 中的值?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!