Home >Web Front-end >JS Tutorial >How to find duplicate elements in an array using javascript

How to find duplicate elements in an array using javascript

陈政宽～Original: 2017-06-28 12:44:053006browse

This article mainly introduces the JS method of finding repeated elements in arrays, and compares and analyzes javascriptfor array traversal and judgment based on specific examples. , sorting and other related operation skills, friends in need can refer to

This article describes the method of finding duplicate elements in an array using JS. Share it with everyone for your reference, the details are as follows:

JS’s data type has an array. Today we will talk about a kind of processing of arrays. I believe many people have encountered finding unique elements from an array, but what I encountered was finding duplicate elements from an array.

There are many ways to find unique elements from js arrays. Here is one:

<!DOCTYPE html>
<html>
<body>
<script>
Array.prototype.deleteEle=function(){
  var newArr = this;
  for (var i=newArr.length-1; i>=0; i--)
  {
    var targetNode = newArr[i];
    for (var j=0; j<i; j++)
    {
      if(targetNode == newArr[j]){
        newArr.splice(i,1);
        break;
      }
    }
  }
  return newArr;
}
var arr = ["a","b","c","c","ab","d","ab","d","c"];
console.log(arr.deleteEle());
</script>
</body>
</html>

The running effect diagram is as follows:

The following is a method of retrieving duplicate elements from a js array:

<!DOCTYPE html>
<html>
<body>
<script>
var a = [5,4,3,2,1,2,3,2,1,];
Array.prototype.duplicate=function() {
  var tmp = [];
  this.concat().sort().sort(function(a,b){
    if(a==b && tmp.indexOf(a) === -1) tmp.push(a);
  });
  return tmp;
}
console.log(a.duplicate())
</script>
</body>
</html>

The running effect is as follows:

The above is the detailed content of How to find duplicate elements in an array using javascript. For more information, please follow other related articles on the PHP Chinese website!

Statement：

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Previous article：Implementation code for javascript to determine time periodNext article：Implementation code for javascript to determine time period

See more

How to find duplicate elements in an array using javascript

Related articles