how to use a list in c#

Hello Francis.

List in C# is like an expandable array. While a normal array has a fixed size, a List grows and shrinks automatically as you add or remove items.

1. Basic Setup

You must include this line at the very top of your code:

using System.Collections.Generic;

2. Example

// 1. Create a new list of strings
List gamers = new List();

// 2. Add items to the list
gamers.Add("Alice");
gamers.Add("Bob");
gamers.Add("Charlie");

// 3. Remove an item
gamers.Remove("Bob");

// 4. Access an item by its position (Index starts at 0)
string firstPlayer = gamers[0]; // Alice

// 5. Use a loop to print every item
foreach (string name in gamers)
{
    Console.WriteLine(name);
}

// 6. Check how many items are inside
Console.WriteLine("Total players: " + gamers.Count);

Essential Methods to Know

• .Add(value): Adds an item to the end of the list.

• .Insert(index, value): Puts an item at a specific position.

• .Remove(value): Removes the first instance of that specific item.

• .RemoveAt(index): Removes the item at a specific position (e.g., gamers.RemoveAt(0)).

• .Clear(): Deletes everything in the list.

• .Contains(value): Returns true or false if the item is in the list.

• .Sort(): Puts the items in alphabetical or numerical order.

Why use a List?

You should use a List whenever you don't know exactly how many items you will need to store ahead of time. It is the most common way to handle collections of data in professional C# development.

Hope this helps. thanks for reading.

Hi Francis Dwight Esmade,

Following examples describe how to use a list in C#:

What is List?

• In System.Collections.Generic, List is a resizable and ordered collection.

• Examples of element type (T) are List, List, or a custom class.

using System;
using System.Collections.Generic;

Create a List

var numbers = new List();                      // empty
var names = new List { "Kapil", "Sachin" };     // with initial items
var capacityList = new List(capacity: 50);     // optional initial capacity (perf)

Add Items in List

numbers.Add(10);
numbers.AddRange(new[] { 5, 20, 10 }); // add multiple

Access & Update Items in List

int first = numbers[0];   // indexer
numbers[1] = 25;          // update at index
int count = numbers.Count; // number of items (not capacity)

Iterate List

foreach (var n in numbers)
     Console.WriteLine(n);

// If you need indexes:
for (int i = 0; i < numbers.Count; i++)
     Console.WriteLine($"[{i}] = {numbers[i]}");

Search & Check List

bool has30 = numbers.Contains(30);   // uses equality of T
int index = numbers.IndexOf(25);     // -1 if not found
int lastIndex = numbers.LastIndexOf(25);

int found = numbers.Find(n => n > 20);        // first match or default
var matches = numbers.FindAll(n => n % 2 == 0); // all evens
int idx = numbers.FindIndex(n => n == 40);

Remove Items from List

numbers.Remove(30);     // removes first occurrence (returns bool)
numbers.RemoveAt(0);    // by index
numbers.RemoveAll(n => n < 25); // predicate-based removal
numbers.Clear();        // empty the list

Sort & Reverse List

numbers.Sort();                         // natural order
numbers.Sort((a, b) => b.CompareTo(a));   // custom comparer (desc)
numbers.Reverse();                      // reverse order

Glad to help! Please mark this answer as the accepted answer if it helped you out!