在 javascript 中查询数组以从中获取我想要的项目的最佳方法是什么? [英] What's the best way to query an array in javascript to get just the items from it I want?

问题描述

我有一个这样的数组(只有 3000 多个对象，而不是这里的 3 个):

I have an array like this (with just over 3000 objects instead of the 3 here):

items = [{name:'charlie', age:'16'}, {name:'ben', age:'18'}, {name:'steve', age:'18'}]

返回仅包含 18 岁人群对象的数组的最佳方法是什么?所以我想要:

What's the best way to return an array with just the objects of people who are 18? So I want:

items = [{name:'ben', age:'18'}, {name:'steve', age:'18'}]

我能想到的最好的就是这个(使用 jQuery):

The best I can think of is this (using jQuery):

newArray = []
$.each(items, function(index, item) {
    if(item.age=='18') {
        newArray.push(item)
    }
})

考虑到有 300 万个对象，而且我将一次最多进行 50 次这样的比较，这就需要大量循环.有没有更好的办法?

Considering that there's 3000 thousand objects, and also that I'll be doing that comparison up to fifty times in one go, that's a lot of looping. Is there a better way?

推荐答案

可以使用纯javascript

You can use pure javascript

var wanted = items.filter( function(item){return (item.age==18);} );

如果您的浏览器不支持 1.6 版本的 javascript，您可以在 https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/filter

And if your browser does not support the 1.6 version of javascript you can find an implementation of the filter method at https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/filter

更新

Speedwise 有一个巨大 变化的^{(在测试中出错)} 与正常循环的区别(取决于浏览器).. 看看我在 http://做的这个小测试jsperf.com/array-filter-vs-loop/3

Speedwise there is a huge varying ^{(had an error in the test)} difference from a normal loop (depending on browser).. Have a look at this little test i made at http://jsperf.com/array-filter-vs-loop/3

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