在JavaScript中两个数组的交集计算 [英] Compute intersection of two arrays in JavaScript

问题描述

由于不等长的两个数组：

Given two arrays of unequal length:

var arr1 = ["mike", "sue", "tom", "kathy", "henry"]; //arr1.length = 5
var arr2 = ["howey", "jim", "sue", "jennifer", "kathy", "hank", "alex"]; //arr2.length = 7

我怎样才能找到共同的价值观念，以两个阵列？在这种情况下起诉和凯西应返回。

推荐答案

下面是一个基于<一个路口功能href=\"https://developer.mozilla.org/en/docs/JavaScript/Reference/Global_Objects/Array/filter\"><$c$c>Array.prototype.filter

Here is an intersection function based on Array.prototype.filter

function intersect(a, b) {
    var t;
    if (b.length > a.length) t = b, b = a, a = t; // indexOf to loop over shorter
    return a.filter(function (e) {
        if (b.indexOf(e) !== -1) return true;
    });
}

var arr1 = ["mike", "sue", "tom", "kathy", "henry"];
    arr2 = ["howey", "jim", "sue", "jennifer", "kathy", "hank", "alex"];

intersect(arr1, arr2); // ["sue", "kathy"]

---

您可能还需要考虑以下

---

You might also want to consider the following

var arr1 = ['sue', 'sue', 'kathy'],
    arr2 = ['kathy', 'kathy', 'sue'];

以上现在会给 [起诉，苏，凯西] 。如果你不想重复，你可以做这样一个进一步过滤。这也将标准化的结果。即。

The above would now give ["sue", "sue", "kathy"]. If you don't want duplicates you could do a further filter on this. This would also standardise results. i.e.

return a
    .filter(/* .. */) // same as before
    .filter(function (e, i, c) { // extra step to remove duplicates
        return c.indexOf(e) === i;
    });

添加此现在将返回相同的结果previous阵列（ [起诉，凯西] ），即使有重复。

Adding this will now return the same result as the previous arrays (["sue", "kathy"]), even though there were duplicates.

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