List

What is a List?

List<T> is a class that contains multiple objects of the same data type that can be accessed using an index. For example,

Create a List

To create List<T> in C#, we need to use the System.Collections.Generic namespace. Here is how we can create List<T>.For example,

using System;
using System.Collections.Generic;
class Program
{
    public static void Main()
    {
        // create a list named subjects that contain 2 elements 
        var subjects = new List<string>();
        subjects.Add("English");
        subjects.Add("Math");
    }
}

OR

using System;
using System.Collections.Generic;
class Program
{
    public static void Main()
    {
        //create a list named subjects that contain 2 elements 
        //object initialization syntax
        var subjects = new List<string>() 
        { 
            "English", 
            "Math" 
        };

    }
}

Access the List Elements

We can access List using index notation []. For example,

using System;
using System.Collections.Generic;

class Program
{
    public static void Main()
    {
        List<string> languages = new List<string>() { "Python", "Java" };

        // access the first and second elements of languages list
        Console.WriteLine("The first element of the list is " + languages[0]);
        Console.WriteLine("The second element of the list is " + languages[1]);
    }
}

Iterate the List

In C#, we can also loop through each element of List<T> using a for loop. For example,

using System;
using System.Collections.Generic;

class Program
{
    public static void Main()
    {
        List<string> albums = new List<string>() { "Red", "Midnight", "Reputation" };

        // iterate through the albums list  
        for (int i = 0; i < albums.Count; i++)
            Console.WriteLine(albums[i]);
    }
}

Note: The Count property returns the total number of elements inside the list.

OR

using System;
using System.Collections.Generic;

class Program
{
    public static void Main()
    {
        List<string> albums = new List<string>() { "Red", "Midnight", "Reputation" };

        // iterate through the albums list  
        foreach (string album in albums)
            Console.WriteLine(album);
    }
}

Basic Operations on List

The List<T> class provides various methods to perform different operations on List. We will look at some commonly used List operations in this tutorial:

• Add Elements

• Insert Elements

• Remove Elements

For details, see:

List<T> Class (System.Collections.Generic)MicrosoftLearn