C# Lists

C# Lists

In C# List is one of the generic collection classes that are present under System.Collections.Generic namespace. A list is used to create a collection of any data type. The object that is stored in the List, can be accessed by its index position just like a normal array. But List can grow automatically.

Let’s look at some examples of the List in C#.

 
using System;
using System.Collections.Generic; //Need to add the namespace

namespace ConsoleAppDemo
{
    class Program
    {
        static void Main(string[] args)
        {

            var someRandomNums = new List();
            someRandomNums.Add(5);
            someRandomNums.Add(10);
            someRandomNums.Add(15);
            someRandomNums.Add(20);

            //One way to access the value of the List collection
            Console.WriteLine(someRandomNums[0]); //Output: 5


            //Seond way to access the value of the List collection using the loops
            foreach (var nums in someRandomNums)
            {
                Console.WriteLine(nums);
            }


            //Third way to access the value of the List collection using the  for loops
            for (int i = 0; i < someRandomNums.Count; i++)
            {
                Console.WriteLine(someRandomNums[i]);
            }

            Console.ReadKey();
        }
    }
}
    

The output of the both the Foreach and For loops:

5
10
15
20

Let's see another example with using collection initializer syntax.

 
using System;
using System.Collections.Generic;

namespace ConsoleAppDemo
{
    class Program
    {
        static void Main(string[] args)
        {

            var programmingLangsLists = new List()
            {
                "C#",
                "JavaScript",
                "Java",
                "Python"
            };

            //One way to access the value of the List collection
            Console.WriteLine(programmingLangsLists[0]); //Output: C#

            //Seond way to access the value of the List collection using the loops
            foreach (var lang in programmingLangsLists)
            {
                Console.WriteLine(lang);
            }

            //Third way to access the value of the List collection using the  for loops
            for (int i = 0; i < programmingLangsLists.Count; i++)
            {
                Console.WriteLine(programmingLangsLists[i]);
            }


            Console.ReadKey();
        }
    }
}
    

The output of the both the Foreach and For loops:

C#
JavaScript
Java
Python

Let's see another example of using the class. We have created the Languages Class for the example.

 
using System;
using System.Collections.Generic;

namespace ConsoleAppDemo
{
    //Languages Class
    class Languages
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {

            var langsLists = new List()
            {
                new Languages(){ Id=1, Name="C#" },
                new Languages(){ Id=2, Name="JavaScript" },
                new Languages(){ Id=3, Name="Java" },
                new Languages(){ Id=4, Name="Python" }
            };

            
            //One way to access the value of the List collection
            Console.WriteLine(langsLists[0].Id + ":" +langsLists[0].Name); //Output: 1:C#


            //Seond way to access the value of the List collection using the loops
            foreach (var lang in langsLists)
            {
                Console.WriteLine(lang.Id + ":" + lang.Name);
            }


            //Third way to access the value of the List collection using the  for loops
            for (int i = 0; i < langsLists.Count; i++)
            {
                Console.WriteLine(langsLists[i].Id + ":" + langsLists[i].Name);
            }


            Console.ReadKey();
        }
    }
} 

The output of the both the Foreach and For loops:

1:C#
2:JavaScript
3:Java
4:Python