Question

I need to calculate the Aggregate of a certain property from an object list by grouping the objects based on another property.. For example, I have a list of 5 objects as below:

list<cls> Objlist = new list<cls>();

 Obj1.Name="earth";
 Obj1.Value = 10;
 objlist.add(Obj1);

 Obj2.Name="sun";
 Obj2.value = 15;
 objlist.add(Obj2);

 Obj3.Name = "earth";
 Obj3.Value = 25;
 objlist.add(Obj3);

 Obj4.Name = "earth";
 Obj4.Value = 35;
 objlist.add(Obj4);

 Obj5.Name="sun";
 Obj5.value = 50;
 objlist.add(Obj5);

What I need is another list to have the avg value of earth and sun objects.. How this can be accomplished using LINQ?

Answer 1

Average is what you need from LINQ, use GroupBy to group by Name first:

var result = Objlist.GroupBy(x => x.Name)
            .Select(g => new {
                                 Name = g.Key, 
                                 Value = g.Average(o => o.Value)
                             });