Analysis of javascript array deduplication method

The example in this article describes the javascript array deduplication method. Share it with everyone for your reference, the details are as follows:

Method 1.

Idea: Create a new empty array, loop through the old array, and use the indexOf() method to get the elements in the array The position in , if the value is -1, it means it does not exist. Then the new array uses indexOf to get each element of the old array. If the value is -1, it means it does not exist, push it into the new array, and finally output the new array, which is the array after deduplication

var arr=[24,56,74,89,24,56,78,09,24];
var new_arr=[];
for(var i=0;i<arr.length;i++){
  if(new_arr.indexOf(arr[i])==-1){
    new_arr.push(arr[i]);
  }
}
console.log(new_arr);

Method 2.

var arr=[2,58,49,26,49];<br>var o={};
var new_arr=[];
for(var i=0;i<arr.length;i++){
  var k=arr[i];
  if(!o[k]){
    o[k]=true;
    new_arr.push(k);
  }
}
alert(new_arr);

The same principle, just borrow an empty object to judge

Note: The second method is to use the It is stored in an object in the form of a subscript. The subscript reference is much faster than searching the array using indexOf(), so the first method is very resource-consuming. I hope this article will be useful to everyone in JavaScript programming. helped.

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