Linq group by query

Question

Trying to work out a linq query and was wondering if you guys could help.

I have a list of objects foo and each foo object has a list of bar. bar has an active date and a numeric value. for example

foo
   bar -> 01/02/05, 10000
   bar -> 04/06/10, 30023
foo
   bar -> 30/01/02, 23494

And I want to write a linq query that will return me a distinct list of dates and the summed total for that date

It may be that its friday, but I'm drawing a blank.

Thanks in advance

score 45 · Accepted Answer · answered Mar 18 '11 at 15:22

45

Looks like you want:

var query = from foo in list
            from bar in foo.Bars
            group bar.Value by bar.Date into dates
            select new { Date = dates.Key, Sum = dates.Sum() };

answered Mar 18 '11 at 15:22

Jon Skeet

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yep, thats the ticket... think I need to go home – mat-mcloughlin Mar 18 '11 at 15:25
@brokem, I'm after the summed total, not the number of dates – mat-mcloughlin Mar 18 '11 at 15:26
@mjmcloug: Yep I realized that once I had already written the comment - removed it right after. – BrokenGlass Mar 18 '11 at 15:34

score 6 · Answer 2 · answered Nov 11 '11 at 00:35

Check it as well...

var q = from e in Entries
          select new
          {
               EntryID = e.EntryID,
               EntryName = e.EntryName,
               EntryDescription = e.EntryDescription,
               VoterID = voterID,
               Score = (int?)(from v in e.Votes
                              where v.VoterID == voterID 
                              select v.Score).FirstOrDefault()

Linq group by query

2 Answers2

Linked