Question

I have following data structure (simplified): A giant list of the class TestClass

public class TestClass
{
   public string Name { get; set; }
   public int Value { get; set; }
   public DateTime Date { get; set; }
}

I’m trying to find a LINQ-Query to get the number of items with the same Name and Value on one day. I tried it with multiple groupby-Statements but I didn’t get it…
Example:

Name  | Value | Date
Alice | 42    | 11.02.1900
Bob   | 4211  | 22.03.2030
Bob   | 4211  | 22.03.2030
Bob   | 42    | 22.03.2030
Bob   | 42    | 22.03.2030
Alice | 4711  | 30.01.2045

This data I want to get (Last number is the important one)

Alice, 42, 11.02.1900, 1
Bob, 4211, 22.03.2030, 3
Bob, 42, 22.03.2030, 2
Alice, 4711, 30.01.2045, 1

Thanks for your help!

Regards

Answer 1

You’re looking for

list.GroupBy(o => new { o.Name, o.Value, o.Date })
    .Select(g => new { g.Key.Name, g.Key.Value, g.Key.Date, Count = g.Count() })