获取重复的数组索引 [英] Get the array index of duplicates

问题描述

在JavaScript数组我如何能得到重复的字符串的索引？

In a JavaScript array how can I get the index of duplicate strings?

例如：

MyArray = ["abc","def","abc"]; //----> return 0,2("abc");

另外一个例子：

My Array = ["abc","def","abc","xyz","def","abc"] 
//----> return 0,2,5("abc") and 1,4("def");

我不知道如何做到这一点。
预先感谢您的帮助！

I have no idea how to do this. Thanks in advance for your help!

推荐答案

另一种方法：

Array.prototype.getDuplicates = function () {
    var duplicates = {};
    for (var i = 0; i < this.length; i++) {
        if(duplicates.hasOwnProperty(this[i])) {
            duplicates[this[i]].push(i);
        } else if (this.lastIndexOf(this[i]) !== i) {
            duplicates[this[i]] = [i];
        }
    }

    return duplicates;
};

它返回一个对象，其中键是重复的条目和值与指数的数组，即

It returns an object where the keys are the duplicate entries and the values are an array with their indices, i.e.

["abc","def","abc"].getDuplicates() -> { "abc": [0, 2] }

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