How to group by custom types with linq

Question

I have this class

public class Item
{
       public Coordinate coordinate { get; set; }
        ...
        ...
}

With Coordinate being def

Answer 1

There is an overload to the GrouBy method that takes an IEqualityComparer as a parameter, but is there the equivalent using the group clause?

You can always group by an anonymous type, if you just want a quick inline solution and aren't worried about hitting the exact type for the keys:

var grouped =
  from it in items 
  group it by new {it.Coordinate.Latitude, it.Coordinate.Longitude};