如何制作具有唯一元素的数组(即删除重复项)? [英] How do I make an array with unique elements (i.e. remove duplicates)?

问题描述

我有这个代码:

var ar = [10,7,8,3,4,7,6];

function isin(n,a){
  for (var i=0;i<a.length;i++){
    if (a[i]== n) {
      var b = true;
      return b;
    } else {
      var c = false;
      return c;
   }
  }
}

function unique(a){
  var arr = [];
  for (var i=0;i<a.length;i++){
    if (!isin(a[i],arr)){
      arr.push(a[i]);
    }
  }

 return arr;
}

alert(unique(ar));

在这段代码中，我尝试从原始数组中创建新的唯一数组(没有重复).但是我还是得到了原来的数组！我的错误在哪里?

In this code, I try to create new unique array (without duplicates) out of the original one. But I still get the original array! Where's my mistake?

推荐答案

使用普通数组并返回关联数组的键(仅包含给定数组中的唯一"值)更有效:

Using a plain array and returning the keys of associative array (containing only the "unique" values from given array) is more efficient:

function ArrNoDupe(a) {
    var temp = {};
    for (var i = 0; i < a.length; i++)
        temp[a[i]] = true;
    var r = [];
    for (var k in temp)
        r.push(k);
    return r;
}

$(document).ready(function() {
    var arr = [10, 7, 8, 3, 4, 3, 7, 6];
    var noDupes = ArrNoDupe(arr);
    $("#before").html("Before: " + arr.join(", "));
    $("#after").html("After: " + noDupes.join(", "));
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="before"></div>
<div id="after"></div>

注意:该函数不保留项目的顺序，所以如果这很重要，请使用不同的逻辑.

Note: The function does not preserve the order of the items, so if this is important use different logic.

从 IE9 和所有其他现代浏览器(例如 Chrome、Firefox)开始，通过使用 Object.keys() 方法，这可以变得更加高效:

As of IE9 and on all other modern browsers (e.g. Chrome, Firefox) this can become even more efficient by using the Object.keys() method:

function ArrNoDupe(a) {
    var temp = {};
    for (var i = 0; i < a.length; i++)
        temp[a[i]] = true;
    return Object.keys(temp);
}

$(document).ready(function() {
    var arr = [10, 7, 8, 3, 4, 3, 7, 6];
    var noDupes = ArrNoDupe(arr);
    $("#before").html("Before: " + arr.join(", "));
    $("#after").html("After: " + noDupes.join(", "));
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="before"></div>
<div id="after"></div>

_{感谢 wateriswet 引起我的注意.:)}

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