Question

What is the LINQ syntax for the Average need below. Both Select and SelectMany fail me.
I can Max() and Sum() my internal list, but Average() wont compile.

The JSON version of the simple list looks like

[{"Week":6, "Matches":[{"Game":189},{"Game":149},{"Game":132}]} ....

var hiGame = games.Max(g => g.Matches.Max(m => m.Game)); // ok
var hiSeries = games.Max(g => g.Matches.Sum(m => m.Game)); // ok
var ave = games.Average(g => g.Matches.SelectMany(m => m.Game)); // no go

The type arguments for method ‘System.Linq.Enumerable.SelectMany(System.Collections.Generic.IEnumerable, System.Func>)’ cannot be inferred from the usage. Try specifying the type arguments explicitly.

Answer 1

I think you want your SelectMany on the outside:

var ave = games.SelectMany(g => g.Matches) // Flatten to a sequence of matches
               .Average(m => m.Game);      // Average by value of Game