Swap array elements using their index in JavaScript

This post will discuss how to swap array elements using their index in JavaScript.

There are several ways to perform a swap operation on an array in JavaScript. Here are some examples of how to swap two elements in an array given their indices:

1. Using a temporary variable

This is a common technique that works in any version of JavaScript. It involves storing one of the elements in a temporary variable, then assigning the other element to its place, and finally assigning the temporary variable to the other element’s place. Here’s an example:

let swapArrayElements = function(arr, indexA, indexB)

{

// store the first element in a temporary variable

let temp = arr[indexA];

// assign the second element to the first element's place

arr[indexA] = arr[indexB];

// assign the temporary variable to the second element's place

arr[indexB] = temp;

};

let arr = [1, 2, 3, 4, 5];

// swap element present at index 1 with index 4

swapArrayElements(arr, 1, 4);

console.log(arr); // [1, 5, 3, 4, 2]

Download Run Code

2. Using ES6 Destructuring Assignment

This is a newer feature of JavaScript that allows swapping two elements in an array in one line, without using a temporary variable. It involves using square brackets to assign the elements to each other in a reverse order. Here’s an example:

let swapArrayElements = function(arr, indexA, indexB)

{

// swap the elements in one line

[arr[indexA], arr[indexB]] = [arr[indexB], arr[indexA]];

};

let arr = [1, 2, 3, 4, 5];

// swap element present at index 1 with index 4

swapArrayElements(arr, 1, 4);

console.log(arr); // [1, 5, 3, 4, 2]

Download Run Code

3. Using `splice()` function

This is another way to swap two elements in an array without using a temporary variable, but it is less efficient than the previous functions. It involves using the splice() function to remove and insert elements at the same time. Here’s an example:

let swapArrayElements = function(arr, indexA, indexB)

{

// remove and insert elements at the same time

arr.splice(indexB, 1, arr.splice(indexA, 1, arr[indexB])[0]);

};

let arr = [1, 2, 3, 4, 5];

// swap element present at index 1 with index 4

swapArrayElements(arr, 1, 4);

console.log(arr); // [1, 5, 3, 4, 2]

Download Run Code

That’s all about swapping array elements in JavaScript.

Swap array elements using their index in JavaScript

1. Using a temporary variable

2. Using ES6 Destructuring Assignment

3. Using splice() function

Share this:

3. Using `splice()` function