Question

There is a list of a class in my software with these properties :

Name — Quantity

list may contains these data :

name1 — 12
name1 — 10
name2 — 10
name2 — 5
I need a output like this :
name1 — 22
name2 — 15

I can make this output with messy code (with for each and etc) but how can I provide this with LINQ query ?

Answer 1

You can use Enumerable.GroupBy and Enumerable.Sum.

It would look similar to:

var values = theCollection
                .GroupBy(item => item.Name)
                .Select(g => new { Name = g.Key, Total = g.Sum(i => i.Value) });

foreach(var value in values)
    Console.WriteLine("{0} - {1}", value.Name, value.Total);