how to use a list in c#

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Pankajkumar Patel · Answer

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 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 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!

Darshan Adakane · Answer

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.

how to use a list in c#

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