Home > Article > Web Front-end > Efficiency testing of several methods to remove duplicates from JavaScript arrays
The following is my summary and efficiency test of three high-efficiency methods on the Internet. If you have better opinions or suggestions, you can also put them forward and let us learn together.
Array deduplication method 1:
Array.prototype.unique1 = function(){ console.time("数组去重法1"); //记录开始执行的时间 var arr = []; //创建一个临时数组 var obj = {}; //创建一个空对象 for(var i = 0; i < this.length; i++){ //遍历当前要去重的数组 if(!obj[this[i]]){ //判断obj对象中是否存有当前项,没有则执行 arr.push(this[i]); //将当前项push到临时数组中 obj[this[i]] = 1; //将当前项存入obj对象 } } console.timeEnd("数组去重法1"); //记录结束执行的时间 return arr; }
Array deduplication method 2:
Array.prototype.unique2 = function(){ console.time("数组去重法2"); //记录开始执行的时间 var arr = []; //创建一个临时数组 for(var i = 0; i < this.length; i++){ //遍历当前要去重的数组 if(arr.indexOf(this[i]) == -1){ //判断临时数组中是否存有当前项,没有则执行 arr.push(this[i]); //将当前项push到临时数组中 } } console.timeEnd("数组去重法2"); //记录结束执行的时间 return arr; }
Array deduplication method 3:
Array.prototype.unique3 = function(){ console.time("数组去重法3"); //记录开始执行的时间 var arr = [this[0]]; //创建一个临时数组,并将要去重数组的第一项存入临时数组 for(var i = 1; i < this.length; i++) { //从要去重数组第二项开始遍历 if (this.indexOf(this[i]) == i){ //判断临时数组中是否存有当前项,没有则执行 arr.push(this[i]); //将当前项push到临时数组中 } } console.timeEnd("数组去重法3"); //记录结束执行的时间 return arr; }
Efficiency test method:
var arr1 = []; //创建一个要去重的数组 for(var i = 0; i < 200000; i++){ //遍历200000个数据 arr1.push(parseInt(Math.random() * 10) + 1); //将所有数据返回为随机数(1-10之间)的数, 并push到要去重的数组中 } console.log(arr1.unique1()); //打印数组去重法1的执行时间 console.log(arr1.unique2()); //打印数组去重法2的执行时间 console.log(arr1.unique3()); //打印数组去重法3的执行时间
Efficiency test results: