How to use splice in js

JavaScript's Splice method allows you to delete or insert elements from an array, returning a new array containing the deleted elements. The usage is as follows: Delete elements: arr.splice(start, deleteCount) Insert elements: arr.splice(start, 0, ...items) Replace elements: arr.splice(start, 1, ...items) Delete from the end Element: arr.splice(-1, deleteCount)Delete element from the beginning: arr.splice(0, deleteCount)

Splice method in JavaScript Usage

The Splice method is a built-in method of the Array object in JavaScript, used to delete or insert elements from the array. It returns a new array containing the deleted elements, and new elements can be inserted in the original order.

Syntax

array.splice(start, deleteCount, ...items)

Parameters

• start: The starting position of deleted elements , starting from 0. If you specify a negative number, counting starts from the end of the array.
• deleteCount: The number of elements to be deleted. If not specified, it will be deleted from the starting position to the end of the array.
• items: Optional parameter used to insert new elements after deletion.

Return value

A new array containing the deleted elements.

How to remove elements using

1. :

   const arr = [1, 2, 3, 4, 5];
   arr.splice(2, 2); // [3, 4]

2. Insert element:

   arr.splice(2, 0, 'a', 'b'); // [1, 2, 'a', 'b', 3, 4, 5]

3. Replace element:
   Delete element and insert new element, which is equivalent to replacement operation:

   arr.splice(2, 1, 'c'); // [1, 2, 'c', 4, 5]

4. Remove elements from the end of the array:
   Use a negative starting position:

   arr.splice(-1, 1); // [1, 2, 'c', 4]

5. Remove elements from the beginning of the array :
   Specify the starting position as 0:

   arr.splice(0, 1); // [2, 'c', 4]

   Note

   • The Splice method will directly modify the original array.
   • The returned array contains the deleted elements, and the original array will be modified.
   • If deleteCount is less than 0 or greater than the array length, it will be ignored.
   • If start is greater than the array length, no operation will be performed.
   • If you want to delete and insert elements at the same time, you should use the spread operator (...) with the new element as argument.

   The above is the detailed content of How to use splice in js. For more information, please follow other related articles on the PHP Chinese website!