exclude an element from a grouping

Question

I am looking for duplicates in a dictionary of type Dictionary<long, MyClass> using MyClass.some_property as the comparison value:

var dict = new Dictionary<long, MyClass>(...);
var duplicates = from d in dict
                 group d by d.Value.some_property into g
                 where g.Count() > 1
                 select g;

Now I need to exclude the first element in each grouping in the duplicates enumerable. How is this done without converting everything to another data structure? I want to avoid using any additional memory.

Answer 1

You can use skip

var dict = new Dictionary<long, MyClass>(...);
var duplicates = from d in dict
                 group d by d.Value.some_property into g
                 where g.Count() > 1
                 select new {Key= g.Key, Values = g.Skip(1)};