Question

I’m dealing with some arrays that are being returned to me from a 3rd party API. Sometimes these come back as null. I am able to handle everything elegantly with LINQ except for the null case. I came up with something like this:

IEnumerable<Thing> procs = APICall(foo, bar);
var result = from proc in procs ?? Enumerable.Empty<Thing>()
    where proc != null
    select Transform(proc);

The use of the coalescing operator here chafes a little. Am I missing something from LINQ that handles this?

Answer 1

This is in effect the same solution that you have, but I use an extension method.

public static partial class EnumerableExtensions
{
    public static IEnumerable<T> EmptyIfNull<T>(this IEnumerable<T> source)
    {
        return source ?? Enumerable.Empty<T>();
    }
}

So that we end up with:

IEnumerable<Thing> procs = APICall(foo, bar);
var result = from proc in procs.EmptyIfNull()
             where proc != null
             select Transform(proc);