C# Tip : List Patterns

List patterns in C# (12 or above) allow you to match elements within a collection using pattern matching syntax. They help you check if a list has certain elements, a specific structure, or a particular number of items—making your code more readable and expressive when working with arrays or lists.

Example

Here's a simple example of list patterns in C#:

int[] numbers = { 1, 2, 3 };

if (numbers is [1, 2, 3])
{
    Console.WriteLine("Exact match: [1, 2, 3]");
}

Explanation:

• The condition numbers is [1, 2, 3] checks if the array exactly matches the pattern: it has three elements, in the same order, with those exact values.

• If it matches, the code inside the if block runs.

Partial match

You can also do partial matches:

if (numbers is [1, ..])
{
    Console.WriteLine("Starts with 1");
}

• .. means "any number of elements after" — this checks if the array starts with 1, regardless of how many elements come after it.

• For more information about List Patterns, refer https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/patterns#list-patterns