Swap two items in a List in C#

This post will discuss how to swap two items in a List in C#.

We can easily write an extension method to swap an element of the list with another element. For example, consider the following code, which swaps the element at index 2 with the element at index 3 in the list using a temporary variable.

using System;

using System.Collections.Generic;

public static class Extensions

{

public static void Swap<T>(this List<T> list, int i, int j)

{

T temp = list[i];

list[i] = list[j];

list[j] = temp;

}

public class Example

{

public static void Main()

{

List<int> nums = new List<int>() { 1, 2, 3, 4, 5 };

nums.Swap(2, 3);

Console.WriteLine(String.Join(", ", nums)); // 1, 2, 4, 3, 5

}

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Note that the extension method needs to go inside a static class. Alternatively, you can simply write: