GroupBy and Count using LINQ

Question

I have a class called Component with following properties:

public class Component
{
    public string VerticalType {get; set;}
    public string ProductCode {get; set;}
}

And I have a list:

public List<Component> ComponentList;

and say have following items in it the list:

Internet   54896
TV         24859
Video      48596
Internet   35969

I have a Dictionary and I want to fill it with VerticalType as key and Count as Value. So my dictionary would look like this:

(Internet,2)
(TV,1)
(Video,1)

I am trying something like this but have no clue how to get the count.

var results = lead.SelectedOffer.ComponentList.GroupBy(
     p => p.VerticalType,
     p => p.VerticalTypeCount,
     (key, g) => new { VerticalType = key, Count =  });

Ousmane D. · Accepted Answer · 2018-12-24T20:37:14.180

2

To get the count in a group, you use the Count() method:

Count = g.Count()

On another note, since all you want is a mapping from VerticalType to the count then I'd suggest going for:

lead.SelectedOffer.ComponentList.GroupBy(p => p.VerticalType)
                  .ToDictionary(g => g.Key, g => g.Count());

or if you want to persist with the IEnumerable of the anonymous types then you still don't need this specific overload of GroupBy you're using in your example code but rather this overload:

lead.SelectedOffer.ComponentList.GroupBy(p => p.VerticalType)
                  .Select(g => new { VerticalType = g.Key, Count = g.Count() });

edited Dec 24 '18 at 20:37

answered Dec 24 '18 at 20:28

Ousmane D.

54,915
8
91
126

1

Perfect. I'll go with the first suggestion – Huma Ali Dec 24 '18 at 20:42
One more thing. I am getting convertion error when I assign it to dictionary of type `Dictionary` – Huma Ali Dec 24 '18 at 20:53
1

@HumaAli yes, that's because the resulting type is `Dictionary` where `string` is the `VerticalType` and the `int` is the corresponding count. – Ousmane D. Dec 24 '18 at 20:54
Ahh Got it. Thanks – Huma Ali Dec 24 '18 at 20:55

GroupBy and Count using LINQ

1 Answers1