查找多个 JavaScript 数组之间的匹配项

织梦狗教程前端问题

2022-01-01

Finding matches between multiple JavaScript Arrays(查找多个 JavaScript 数组之间的匹配项)

本文介绍了查找多个 JavaScript 数组之间的匹配项的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

I have multiple arrays with string values and I want to compare them and only keep the matching results that are identical between ALL of them.

Given this example code:

var arr1 = ['apple', 'orange', 'banana', 'pear', 'fish', 'pancake', 'taco', 'pizza'];
var arr2 = ['taco', 'fish', 'apple', 'pizza'];
var arr3 = ['banana', 'pizza', 'fish', 'apple'];

I would like to to produce the following array that contains matches from all given arrays:

['apple', 'fish', 'pizza']

I know I can combine all the arrays with var newArr = arr1.concat(arr2, arr3); but that just give me an array with everything, plus the duplicates. Can this be done easily without needing the overhead of libraries such as underscore.js?

(Great, and now i'm hungry too!)

EDIT I suppose I should mention that there could be an unknown amount of arrays, I was just using 3 as an example.

解决方案

var result = arrays.shift().filter(function(v) {
    return arrays.every(function(a) {
        return a.indexOf(v) !== -1;
    });
});

DEMO: http://jsfiddle.net/nWjcp/2/

You could first sort the outer Array to get the shortest Array at the beginning...

arrays.sort(function(a, b) {
    return a.length - b.length;
});

For completeness, here's a solution that deals with duplicates in the Arrays. It uses .reduce() instead of .filter()...

var result = arrays.shift().reduce(function(res, v) {
    if (res.indexOf(v) === -1 && arrays.every(function(a) {
        return a.indexOf(v) !== -1;
    })) res.push(v);
    return res;
}, []);

DEMO: http://jsfiddle.net/nWjcp/4/

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