How to delete an element in an array in js

How to delete an element in an array in js. This article mainly shares with you examples of how to delete an element in an array in js.

First, you can define a function for the js array object to find the position of the specified element in the array, that is, the index. The code is:

Array.prototype.indexOf = function(val) {
for (var i = 0; i < this.length; i++) {
if (this[i] == val) return i;
}
return -1;
};

Then use to get the index of this element , use the inherent function of the js array to delete this element:
The code is:

Array.prototype.remove = function(val) {
var index = this.indexOf(val);
if (index > -1) {
this.splice(index, 1);
}
};

In this way, such a function is constructed. For example, I have an array:

var emp = ['abs','dsf','sdf','fd']

If we To delete 'fd', you can use:

//code from http://caibaojian.com/js-splice-element.html
emp.remove('fd');

An item of the deleted array

splice(index,len,[item]) Note: This method will change the original array .

splice has 3 parameters, it can also be used toreplace/delete/addone or several values ​​in the array·

index: array start index len : Replacement/deletion length item: Replacement value, if the delete operation is performed, the item will be empty

For example: arr = ['a','b','c','d']

Delete

//删除起始下标为1，长度为1的一个值(len设置1，如果为0，则数组不变)
var arr = ['a','b','c','d'];
arr.splice(1,1);
console.log(arr);  
//['a','c','d']; 

//删除起始下标为1，长度为2的一个值(len设置2)
var arr2 = ['a','b','c','d']
arr2.splice(1,2);
console.log(arr2); 
//['a','d']

Replace

//替换起始下标为1，长度为1的一个值为‘ttt’，len设置的1
var arr = ['a','b','c','d'];
arr.splice(1,1,'ttt');
console.log(arr);        
//['a','ttt','c','d'] 

var arr2 = ['a','b','c','d'];
arr2.splice(1,2,'ttt');
console.log(arr2);       
//['a','ttt','d'] 替换起始下标为1，长度为2的两个值为‘ttt’，len设置的1

Add---- len is set to 0, item is the added value

var arr = ['a','b','c','d'];
arr.splice(1,0,'ttt');
console.log(arr);        
//['a','ttt','b','c','d'] 表示在下标为1处添加一项'ttt'

2：delete Will change

var arr = ['a','b','c','d'];
delete arr[1];
arr;  
//["a", undefined × 1, "c", "d"] 中间出现两个逗号，数组长度不变，有一项为undefined

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javascript array method

1. javascript array deduplication

2. Complete list of common javascript codes

Updated 2016-11-17

: High score on stackoverflow In the answer, I saw a code written by the father of jquery John Resig in an article:

// Array Remove - By John Resig (MIT Licensed)Array.prototype.remove = function(from, to) {
  var rest = this.slice((to || from) + 1 || this.length);
  this.length = from < 0 ? this.length + from : from;
  return this.push.apply(this, rest);};

Here are some actual use cases:

// 移除数组中的第二项array.remove(1);// 移除数组中的倒数第二项array.remove(-2);// 移除数组中的第二项和第三项（从第二项开始，删除2个元素）array.remove(1,2);// 移除数组中的最后一项和倒数第二项（数组中的最后两项）array.remove(-2,-1);

This example is the same as the above The first one is quite similar, but it does not check the specific item of the element, but locates the deletion based on the subscript position of the element in the array.

Related recommendations:

5 JavaScript algorithms for deleting duplicate elements in arrays

PHP example code for deleting specified subscript elements in an array

phpHow to delete an element in an array Usage summary

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