Get the highest ranked items per group in linq

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I need to select items with the highest rank per attribute
I have a functional ranking in linq that looks like this:

C#

MyCollection.GroupBy(c => c.Attribute).Select(g => g.OrderByDescending(c => c.Prio).First())

And it works fine except when I get ties in the ranking I only get one of the tied items.

Does anyone know how to get all of the tied items with the highest priority?

What I have tried:

C#

MyCollection.GroupBy(c => c.Attribute).Select(g => g.OrderByDescending(c => c.Prio).First())

Posted 13-May-18 22:43pm

Jörgen Andersson

Updated 13-May-18 23:51pm

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OriginalGriff · Accepted Answer · 2018-05-13T23:52:00

Solution 1

You can't do it automatically, because you have very specifically told it to only return one element from each group - that's what First does!
Try this:

MyCollection.GroupBy(c => c.Attribute).SelectMany(g => g.Where(p => p.Prio == g.Max(h => h.Prio)))

Posted 13-May-18 23:52pm

OriginalGriff

Comments

Jörgen Andersson 14-May-18 6:32am

Oh, I knew it was wrong alright, I just couldn't wrap my head around to get it right.
I have meanwhile solved it though, using a nested Groupby. But your solution is better and as simple as I thought it should be.

OriginalGriff 14-May-18 6:35am

:laugh:
Ain't it always the way? When you ask the question, it solves itself...