LINQ's Distinct() on a particular property

Question

I am playing with LINQ to learn about it, but I can\'t figure out how to use Distinct when I do not have a simple list (a simple list of integers is pretty easy

Answer 1

You can do this with the standard Linq.ToLookup(). This will create a collection of values for each unique key. Just select the first item in the collection

Persons.ToLookup(p => p.Id).Select(coll => coll.First());