Two Methods for deleting repeated array values (deduplication) using JavaScript

The criptarray type does not provide the de-duplicated value method. We need to write a function to delete the array's repeated value. This article introduces the two JavaScript methods used by coders to delete the array's repeated values (de-duplicated) for more information, see. Javascript array deduplication Method 1:

The Array type does not provide the deduplication method. If you want to remove the repeated elements of the Array, you have to find a solution:

Method 1: Use the indexOf method;

var aa=[1,3,5,4,3,3,1,4]function arr(arr) {  var result=[]  for(var i=0; i

Method 2 of removing the javascript array:

function unique(arr) { var result = [], isRepeated; for (var i = 0, len = arr.length; i < len; i++) { isRepeated = false; for (var j = 0, len = result.length; j < len; j++) { if (arr[i] == result[j]) { isRepeated = true; break; } } if (!isRepeated) { result.push(arr[i]); } } return result;}

Method 2: The general idea is to move the array elements one by one to another. During the handling process, check whether the elements are repeated. If yes, they are discarded directly. From nested loops, we can see that this method is very inefficient. We can use a hashtable structure to record existing elements, so as to avoid inner loops. Exactly, implementing hashtable in Javascript is extremely simple, and the improvements are as follows:

function unique(arr) { var result = [], hash = {}; for (var i = 0, elem; (elem = arr[i]) != null; i++) { if (!hash[elem]) { result.push(elem); hash[elem] = true; } } return result;}

The above is all the content of the article, hoping to help the coders.