Lists | Collections | Csharp Tutorial

Introduction to Lists

In C#, a List is a collection class that provides functionality similar to arrays, but with additional features that make it more flexible and easier to work with. Lists are part of the System.Collections.Generic namespace and can hold elements of any data type. Unlike arrays, Lists can dynamically resize, allowing you to add and remove elements as needed.

Creating a List

To create a List, you need to first include the System.Collections.Generic namespace. Then, you can declare and initialize a List using the List class, where T is the type of elements in the List.

using System.Collections.Generic;

List numbers = new List();

Adding Elements to a List

You can add elements to a List using the Add method. The Add method appends elements to the end of the List.

numbers.Add(1);

numbers.Add(2);

numbers.Add(3);

Accessing Elements in a List

Elements in a List can be accessed using the indexer, similar to arrays. The first element has an index of 0.

int firstNumber = numbers[0];

Removing Elements from a List

Elements can be removed from a List using the Remove method, which removes the first occurrence of a specified element. You can also use RemoveAt to remove an element at a specific index.

numbers.Remove(2);

numbers.RemoveAt(0);

Iterating Over a List

You can iterate over a List using a foreach loop to access each element in the List.

foreach (int number in numbers)

{

Console.WriteLine(number);

}

Other Useful List Methods

Lists come with a variety of useful methods for manipulating and querying the collection:

Count: Gets the number of elements in the List.
Contains: Determines whether an element is in the List.
Insert: Inserts an element into the List at a specified index.
Clear: Removes all elements from the List.
Sort: Sorts the elements in the List.

int count = numbers.Count;

bool containsThree = numbers.Contains(3);

numbers.Insert(1, 5);

numbers.Clear();

numbers.Sort();

Conclusion

Lists in C# are a powerful and flexible way to work with collections of data. They offer dynamic resizing, ease of use, and a variety of methods for manipulating elements. By understanding how to create, add, access, remove, and iterate over Lists, you can effectively manage collections of data in your C# programs.

Comprehensive Tutorial on Lists in C#