Question

I have a linq that create a list of object (9 element right now) such as :

Object 1:   Title: Title1
            Value: Marco

Object 2:   Title: Title2
            Value: Paolo

Object 3:   Title: Title3
            Value: Giovanni

Object 4:   Title: Title1
            Value: Edoardo

Object 5:   Title: Title2
            Value: Chris

Object 6:   Title: Title3
            Value: John

Object 7:   Title: Title1
            Value: Manuel

Object 8:   Title: Title2
            Value: Lorenz

Object 9:   Title: Title3
            Value: Ernest

Instead of this 9 object, I’d like to return only 3 Object (group by Title), having as Value for each object the union list for each Value on each Grouping. So the result should be somethings like :

Object 1:   Title: Title1
            Value[]: Marco, Edoardo, Manuel

Object 2:   Title: Title2
            Value[]: Paolo, Chris, Lorenz

Object 3:   Title: Title3
            Value[]: Giovanni, John, Ernest

is it possible on Linq? Or I need to iterate my list and manage it manually?

P.S. Note this is only an example! In my scenario, for each Object I have More element than Title and Value, such as 10 element.

Answer 1

var query = objects.GroupBy(o => o.Title)
                   .Select(g => new  
                   {
                       Title = g.Key,
                       Value = g.Select(x => x.Value).ToArray()
                   });

Or with query syntax:

var query = from o in objects
            group o by o.Title into g
            select new 
                   {
                       Title = g.Key,
                       Value = g.Select(x => x.Value).ToArray()
                   });

UPDATE Consider using simple grouping – this will return objects grouped by title

var query = objects.GroupBy(o => o.Title);