How to delete specified elements of an array in javascript

Two methods for javascript to delete specified elements from an array: 1. Use the splice() function to delete the element at the specified position. The syntax is "array variable name.splice(starting position of deleted element, 1)"; 2. Use the delete keyword to delete the element with the specified subscript, the syntax is "delete array variable name [delete the subscript of the element]".

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

Method 1: splice method

//获取元素在数组的下标
Array.prototype.indexOf = function(val) {
	for (var i = 0; i < this.length; i++) {
		if (this[i] == val)	{ 
			return i;
		};
	}
	return -1; 
};

//根据数组的下标，删除该下标的元素
Array.prototype.remove = function(val) {
	var index = this.indexOf(val);
	if (index > -1) {
	this.splice(index, 1);
	}
};

//测试数据
var insertAttaList = ['abs','dsf',,'abc','sdf','fd'];
insertAttaList.remove('abc');

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

splice has 3 parameters, it can also be used to replace/delete/add one or several values ​​in the array

• index: Array starts next Standard

• len: length of replacement/deletion

• item: replacement value

delete If the operation is performed, the item is empty

For example:

arr = [‘a’,‘b’,‘c’,‘d’]

Delete ---- item is not set

arr.splice(1,1) //[‘a’,‘c’,‘d’] 删除起始下标为1，长度为1的一个值，len设置的1，如果为0，则数组不变
arr.splice(1,2) //[‘a’,‘d’] 删除起始下标为1，长度为2的一个值，len设置的2

[Recommended learning: javascript advanced tutorial]

Replace---- item is the replaced value

arr.splice(1,1,‘ttt’) //[‘a’,‘ttt’,‘c’,‘d’] 替换起始下标为1，长度为1的一个值为‘ttt’，len设置的1
arr.splice(1,2,‘ttt’) //[‘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

arr.splice(1,0,‘ttt’) //[‘a’,‘ttt’,‘b’,‘c’,‘d’] 表示在下标为1处添加一项‘ttt’

Method 2: delete method

deleteAfter deleting an element in the array, the subscripted value will be set to undefined, and the length of the array will not change

For example:

delete arr[1] //[‘a’, ,‘c’,‘d’]

There are two commas in the middle, the length of the array remains unchanged, and one item is undefined

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