CODEWITHSUNDEEP
.netlinqlinq-to-objects
Espo
Espo

Reputation: 41939

Filter linq list on property value

I have a List<int> and a List<customObject>. The customObject class has an ID property. How can I get a List<customObject> containing only the objects where the ID property is in the List<int> using LINQ?

Edit: I accepted Konrads answer because it is easier/more intuitive to read.

Upvotes: 20

Views: 44270

Answers (6)

Robin Winslow
Robin Winslow

Reputation: 11502

using System.Linq;

objList.Where(x => intList.Contains(x.id));

Upvotes: 15

Diana
Diana

Reputation: 1

Please note that using the join instead of contains DOES NOT work when the count of items in the list exceeds 49! You will get the error: Some part of your SQL statement is nested too deeply. Rewrite the query or break it up into smaller queries.

Upvotes: 0

Konrad Rudolph
Konrad Rudolph

Reputation: 546083

var result = from o in objList where intList.Contains(o.ID) select o

Upvotes: 17

Henryk
Henryk

Reputation: 1139

I have had a similar problem just now and used the below solution. If you already have the list of objects you can remove all not found in the int list, leaving just matches in objList.

objList.RemoveAll(x => !intList.Contains(x.id));

Upvotes: 10

Lucas
Lucas

Reputation: 17434

Just for completeness (and maybe it's easier to read?), using a "where" similar to Matt's "join":

var matches = from o in customObjectList
              from i in intList
              where o.ID == i
              select o;

Upvotes: 2

Matt Hamilton
Matt Hamilton

Reputation: 204259

Untested, but it'll be something like this:

var matches = from o in objList 
                  join i in intList on o.ID equals i
                  select o;

@Konrad just tested it, and it does work - I just had a typo where I'd written "i.ID" rather than "i".

Upvotes: 6

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