How to remove duplicate values from several arrays in JavaScript _ javascript skills

The following small series will provide you with a JavaScript array to remove duplicate values. I think it is quite good. Now I will share it with you and give you a reference. It is a common requirement to repeat arrays together with a small Editor. We will temporarily consider repeat arrays of the same type. It mainly aims to clarify the ideas and consider the performance. The following methods are available on the Internet. Here is a brief summary.

Ideas:

1. traverse the array, compare them one by one, and delete
2. traverse the array, compare them one by one, compare them to the same ones, skip the previous duplicate, and put the different ones into the new array.
3. Add an array element to the new array, traverse the remaining array element, and compare it with the elements of the new array one by one. If there are different elements, add the new array.
4. traverse the array and take an element as the object attribute to determine whether the attribute exists.

1. Delete the following duplicate:

Function ov1 (arr) {// var a1 = (new Date). getTime () for (var I = 0; I
2. This is a conventional method and is easy to understand. If the same method is used, the loop jumps out.
function ov2(a) {  //var a1=((new Date).getTime())  var b = [], n = a.length, i, j;  for (i = 0; i < n; i++) {    for (j = i + 1; j < n; j++)      if (a[i] === a[j]){j=false;break;}    if(j)b.push(a[i]);    }  //console.info((new Date).getTime()-a1)    return b.sort(function(a,b){return a-b});} 
3. It took me a long time to understand this. Although the j loop continues here, the I value has changed. It is like a new I loop:
function ov3(a) {  //var a1=((new Date).getTime())  var b = [], n = a.length, i, j;  for (i = 0; i < n; i++) {    for (j = i + 1; j < n; j++)    if (a[i] === a[j])j=++i  b.push(a[i]);}  //console.info((new Date).getTime()-a1)    return b.sort(function(a,b){return a-b});}   
4. Ensure that the new array is unique.
Function ov4 (ar) {// var a1 = (new Date). getTime () var m = [], f; for (var I = 0; I
5. Use object attributes
function ov5(ar){//  var a1=(new Date).getTime()var m,n=[],o= {};for (var i=0;(m= ar[i])!==undefined;i++)if (!o[m]){n.push(m);o[m]=true;}//  console.info((new Date).getTime()-a1)  return n.sort(function(a,b){return a-b});;}
The recommended method for removing repeated values in the above JavaScript arrays is all the content shared by Alibaba Cloud xiaobian. I hope to give you a reference and support for the script.