C# 12 features: Collection expressions
Part 2 of a C# 12 series explaining collection expressions, including how [] initialization works across arrays and other collection types with practical examples.
Part 2 in a series on new language features in C# 12.
Collection expressions
You can now use square brackets [] to initialise a collection! Usually square brackets indicate an array, but the collection expression can be assigned to other collection types too.
You can use them to assign values to fields or in method bodies.
private List<int> numbersList = [1, 2, 3, 4, 5];Like primary constructors, I’ve also found these quite useful in new .NET 8 projects.
Further reading
Example source
https://github.com/flcdrg/csharp-12/blob/main/02-collection-expressions/CollectionExpressions.cs