IndexOf (), remove (), splice () methods for JavaScript arrays

JS, delete an element in the array by value

Array.prototype.indexOf = function (val) {
for (var i = 0; i < this.length; i++) {
if (this[i] = = val) return i;
}
return-1;
};
Array.prototype.remove = function (val) {
var index = This.indexof (val);
if (Index >-1) {
This.splice (index, 1);
}
};

Such as:
var array = [1, 2, 3, 4, 5];
Array.remove (3);

JavaScript Splice () method definition and usage

The splice () method adds/deletes an item to/from the array, and then returns the item that was deleted.

Note: This method changes the original array.

Grammar

Arrayobject.splice (index,howmany,item1,....., ItemX)

Parameters	Description
Index	Necessary. An integer that specifies the location of the Add/remove item, using a negative number to specify the position from the end of the array.
Howmany	Necessary. The number of items to delete. If set to 0, the item is not deleted.
Item1, ..., ItemX	Optional. Adds a new item to the array.

return value

type	Description
Array	A new array containing the deleted items, if any.

Description

The splice () method deletes 0 or more elements starting at index and replaces the deleted elements with one or more values declared in the argument list.

If the element is removed from the Arrayobject, the array containing the deleted element is returned.

Technical details

JavaScript version:	1.2

Browser support

All major browsers support the splice () method.

Hints and Notes

Note : Notice that the splice () method works differently than the slice () method, and the splice () method modifies the array directly.

Example 1

In this example, we will create a new array and add an element to it:

<script type= "Text/javascript" >var arr = new Array (6) arr[0] = "George" arr[1] = "John" arr[2] = "Thomas" arr[3] = "Jame S "arr[4] =" Adrew "arr[5] =" Martin "document.write (arr +" <br/> ") arr.splice(2,0,"William") document.write (arr +" <br/> ") </ Script>

Output:

George,john,thomas,james,adrew,martingeorge,john,william,thomas,james,adrew,martin

Example 2

In this example we will delete the element at index 2 and add a new element to replace the deleted element:

<script type= "Text/javascript" >var arr = new Array (6) arr[0] = "George" arr[1] = "John" arr[2] = "Thomas" arr[3] = "Jame S "arr[4] =" Adrew "arr[5] =" Martin "document.write (arr +" <br/> ") arr.splice(2,1,"William") document.write (arr) </script>

Output:

George,john,thomas,james,adrew,martin
George,john,william,james,adrew,martin

Example 3

In this example we will delete the three elements starting with index 2 ("Thomas") and add a new element ("William") to replace the deleted element:

<script type= "Text/javascript" >var arr = new Array (6) arr[0] = "George" arr[1] = "John" arr[2] = "Thomas" arr[3] = "Jame S "arr[4] =" Adrew "arr[5] =" Martin "document.write (arr +" <br/> ") arr.splice(2,3,"William") document.write (arr) </script>

Output:

George,john,thomas,james,adrew,martin
George,john,william,martin

IndexOf (), remove (), splice () methods for JavaScript arrays