List & IEnumerable

List

When to use:: When you need to perform operations that require adding, removing or modifying elements frequently.

A list is a collection of elements that allows direct access and manipulation of data elements using an index. Unlike arrays, it shrinks and grows dynamically as you add or remove data.

List<int> numbersList = new List<int> {10, 15, 18, 21, 25};

numbersList.add(30); // Add a number to the list

numbersList.remove(10) // Remove a number from the list

bool hasTen = numbersList.Contains(10); // Check if a number is in the list

Console.WriteLine(numbersList[2]); // Direct access to the 3rd element in the list

numbersList.Insert(20, 3); // Insert 3 at the third position

IEnumerable

When to use:: When you ony need to iterate over a collection and don't need to modify the elements.

IEnumerable is a memory efficient way of stepping through a collection of elements

How to create a new IEnumerable -

IEnumerable<string> nameCollection = new List<string> { "Name A", "Name B", "Name C", "Name D" };

Or a new IEnumerable can be created using an already existing collection -

List<int> numberList = new List<int>() {1, 2, 3, 4, 5 };

IEnumerable<int> numberEnumerable = numberList;

IEnumerable vs List

IEnumerable is best when it comes to loading data, and List is best for manipulating data.

Aspect	IEnumerable	List
Loading Data	Lazily loads each item when required	Promptly loads all items at once
Accessing Data	Forward-only, one item at a time	Direct and random access to any item
Best for	Large datasets due to its efficient resource usage	Small to medium datasets requiring frequent data manipulation

Last modified: 23 September 2024