Is there an "Empty List" singleton in C#?
Solution 1:
You are looking for Enumerable.Empty<T>().
In other news the Java empty list sucks because the List interface exposes methods for adding elements to the list which throw exceptions.
Solution 2:
Enumerable.Empty<T>() is exactly that.
Solution 3:
I think you're looking for Enumerable.Empty<T>().
Empty list singleton doesn't make that much sense, because lists are often mutable.
Solution 4:
In your original example you use an empty array to provide an empty enumerable. While using Enumerable.Empty<T>() is perfectly right, there might other cases: if you have to use an array (or the IList<T> interface), you can use the method
System.Array.Empty<T>()
which helps you to avoid unnecessary allocations.
Notes / References:
- the documentation does not mention that this method allocates the empty array only once for each type
- roslyn analyzers recommend this method with the warning CA1825: Avoid zero-length array allocations
- Microsoft reference implementation
- .NET Core implementation