CODEWITHSUNDEEP
vb.netlinqlinq-to-objects
Nick
Nick

Reputation: 4223

LINQ to Objects - Does Not Contain?

I have a collection of Items that each have a collection of Relationships. I have a list of Groups that Items can have Relationships with.

I can find all the Items that have a particular relationship but I now want to find all the Items that don't have a Relationship with any of my Groups.

I can find the Items that have a relationship with any of the Groups by doing this:

Dim groupIds as List(of Integer) = (From g In cmdbGroups Select g.ID).ToList
Dim haveGroup = (From item In items _
                 Where item.Relationships.Any(Function(r) groupIds.Contains(r.TargetID)) _
                 Select item).ToList

How can I find all the items that do not have a relationship with any of the groups?

Upvotes: 2

Views: 16986

Answers (5)

Rei Salazar
Rei Salazar

Reputation: 101

Dim listIds as List(of Integer) = (From g In cmdbGroups Select g.ID).ToList
Dim haveGroup = (From item In items _
    Where Not listIds.Contains(item.ID) 
    Select item.ID).ToList

Upvotes: 0

Joe Chung
Joe Chung

Reputation: 12123

Dim notHasGroup = items.Except(haveGroup)

Upvotes: 2

LukeH
LukeH

Reputation: 269498

If you're generating the haveGroup collection anyway then you could just do something like this:

Dim groupIds as List(of Integer) = (From g In cmdbGroups Select g.ID).ToList

Dim haveGroup = (From item In items _
    Where item.Relationships.Any(Function(r) groupIds.Contains(r.TargetID)) _
    Select item).ToList

Dim haveNotGroup = items.Except(haveGroup).ToList

Upvotes: 2

StriplingWarrior
StriplingWarrior

Reputation: 156624

I don't remember VB all that well, but a simple "Not" should work.

Dim groupIds as List(of Integer) = (From g In cmdbGroups Select g.ID).ToList
Dim haveGroup = (From item In items _
             Where Not item.Relationships.Any(Function(r) groupIds.Contains(r.TargetID)) _
             Select item).ToList

Upvotes: 6

Andrew Hare
Andrew Hare

Reputation: 351566

Have you tried negating the results of the Contains method?

Dim groupIds as List(of Integer) = (From g In cmdbGroups Select g.ID).ToList
Dim haveGroup = (From item In items _
                 Where item.Relationships.Any(Function(r) Not groupIds.Contains(r.TargetID)) _
                 Select item).ToList

Upvotes: 6

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