LINQ query for getting only newest items

Question

I have problem with thinking up LINQ query for getting only newest items.
Example of data what I have (left) and what I need to select (right):

Name  Notes DateRecorded  Name  Notes DateRecorded
Item1 A     1.1.2015      Item1 C     1.3.2015
Item1 B     1.2.2015      Item2 X     1.2.2015
Item1 C     1.3.2015
Item2 X     1.2.2015  

Class Properties
  Name As String
  Notes As String
  DateRecorded As Date
End Class

What do you mean by "newest" items ? Is it the items with a date recorded <= X days ? Or the X last items on your list ? — Tom C.
– Tom C., Commented Oct 6, 2015 at 8:12
I would sort the collection based on the date and then grab the N first elements based on what you need. — nathan
– nathan, Commented Oct 6, 2015 at 8:14
By newest I mean items, that have latest DateRecorded column. So 1.3.2015 is newest for Item1. — Ondřej
– Ondřej, Commented Oct 6, 2015 at 8:42

Tim Schmelter · Accepted Answer · 2015-10-06 08:32:33Z

3

So you want to group by Name and select the newest by DateRecorded:

Dim newestProps = props.GroupBy(Function(p) p.Name).
    Select(Function(grp) grp.OrderByDescending(Function(p) p.DateRecorded).First())

In query syntax:

newestProps = From p In props
              Order By p.DateRecorded Descending
              Group p By p.Name Into orderedNameGroup = Group
              Select orderedNameGroup.First()

edited Oct 6, 2015 at 8:32

answered Oct 6, 2015 at 8:25

Tim Schmelter

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