如何在两个数组中找到匹配的值? [英] How can I find matching values in two arrays?

问题描述

我有两个数组，我希望能够比较两者并只返回匹配的值.例如，两个数组的值都是 cat，因此将返回该值.我没有找到这样的东西.返回相似性的最佳方法是什么?

I have two arrays, and I want to be able to compare the two and only return the values that match. For example both arrays have the value cat so that is what will be returned. I haven't found anything like this. What would be the best way to return similarities?

var array1 = ["cat", "sum","fun", "run"];
var array2 = ["bat", "cat","dog","sun", "hut", "gut"];

//if value in array1 is equal to value in array2 then return match: cat

推荐答案

当然，我的方法是遍历第一个数组一次并检查第二个数组中每个值的索引.如果索引是 >-1，然后push到返回的数组上.

Naturally, my approach was to loop through the first array once and check the index of each value in the second array. If the index is > -1, then push it onto the returned array.

​Array.prototype.diff = function(arr2) {
    var ret = [];
    for(var i in this) {   
        if(arr2.indexOf(this[i]) > -1){
            ret.push(this[i]);
        }
    }
    return ret;
};

我的解决方案不像其他人那样使用两个循环，因此它可能运行得更快一些.如果您想避免使用 for..in，您可以先对两个数组进行排序以重新索引它们的所有值:

​ My solution doesn't use two loops like others do so it may run a bit faster. If you want to avoid using for..in, you can sort both arrays first to reindex all their values:

Array.prototype.diff = function(arr2) {
    var ret = [];
    this.sort();
    arr2.sort();
    for(var i = 0; i < this.length; i += 1) {
        if(arr2.indexOf(this[i]) > -1){
            ret.push(this[i]);
        }
    }
    return ret;
};

用法如下:

var array1 = ["cat", "sum","fun", "run", "hut"];
var array2 = ["bat", "cat","dog","sun", "hut", "gut"];

console.log(array1.diff(array2));

如果您在扩展 Array 原型时遇到问题，可以轻松地将其更改为函数.

If you have an issue/problem with extending the Array prototype, you could easily change this to a function.

var diff = function(arr, arr2) {

并且您可以将 func 最初表示 this 的任何地方更改为 arr2.

And you'd change anywhere where the func originally said this to arr2.

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