How to count and group using vb.net - vb.net

Question

I have the following data returned from a web service and serialized into a list:
Name Severity Type
John Doe Warning A
John Doe Error A
John Doe Error A
John Doe Error A
Jane West Error B
Mike Smith Warning B
Jack Black Warning A
In vb.net, I want to summarize it into the following:
Name TypeAWarning TypeAError TypeBWarning TypeBError
John Doe 1 3
Jane West 1
Mike Smith 1
Jack Black 1
Using linq, how can I take this collection and summarize it? I tried something like:
Dim data As New List(Of TempData)
data.add(new TempData ({TypeAWarning = from d in data Group d By Name = a.Severity into Group??
I am just not sure if linq is the way to go. Can someone point me in the right direction?
Thanks!

Answer 1

You can use a GroupBy to group items by Name field, then knowing each group contains the key (Name field) and all items of the group, you can use this query to shape the result:
Dim Result = Items.GroupBy(Function(item) item.Name) _
.Select(Function(group) New TempData() With
{
.Name = group.Key,
.TypeAWarning = group.Where(Function(item) item.Type = "A" And item.Severity = "Warning").Count(),
.TypeAError = group.Where(Function(item) item.Type = "A" And item.Severity = "Error").Count(),
.TypeBWarning = group.Where(Function(item) item.Type = "B" And item.Severity = "Warning").Count(),
.TypeBError = group.Where(Function(item) item.Type = "B" And item.Severity = "Error").Count()
}).ToList()