LINQ check if int? is in List C#

Question

I have object with ID = 5, ID = 6 and List 1,5. Since list has 5 i need to have object with ID = 5 as a result, but if my list has 5 and 6 i need to have both objects as a result. Hope i'm clear enough.

So something like this:

result = result.Where(r=>r.ID ***IS IN LIST<int>***).OrderBy(r=>r.ID);

Any help is appreciated.

so you want to return elements that exist in both your object and your list? — user1666620, Aug 27 '15 at 13:29
The others responds are correct. If you want more complex behaviour with finding something in inner list, this is real-life example what I use : `Sessions.Where(x => x.Performers.Where(y => y.PerformerId == performerId).FirstOrDefault() != null)` — libik, Aug 27 '15 at 13:30
Just what i was looking for, nice and easy, couldn't manage to get it myself. Thank you all — azza idz, Aug 27 '15 at 13:44
@libik: I would suggest instead ..`.FirstOrDefault() != null` to call `.Any()` — alek kowalczyk, Aug 27 '15 at 14:14

deramko · Answer 1 · 2021-01-28T11:21:39.123

7

result = result.Where(r=>listOfId.Contains(r.ID)).OrderBy(r=>r.ID);

edited Jan 28 '21 at 11:21

answered Aug 27 '15 at 13:29

deramko

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result = result.Where(r=>listOfId.Contains(r.ID)).OrderBy(r=>r.ID); – Charkins12 Jan 27 '21 at 14:21
1

Fixed the missing bracket, thanks @Charkins12 – deramko Jan 28 '21 at 11:22

score 3 · Answer 2 · answered Aug 27 '15 at 13:29

3

 result = result.Where(r=>yourList.Contains(r.ID)).OrderBy(r=>r.ID)

answered Aug 27 '15 at 13:29

alek kowalczyk

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score 3 · Answer 3 · answered Aug 27 '15 at 13:29

3

You can try like this:

result = result.Where(r => somelist.Contains(r.ID)).OrderBy(r => r.ID)

Check List(Of T).Contains Method for details.

answered Aug 27 '15 at 13:29

Rahul Tripathi

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score 2 · Answer 4 · answered Aug 27 '15 at 13:35

2

something easier to read

var results=(from m in MyObjects
            Where myList.Contains(m.Id)
            select m).ToList() ;

answered Aug 27 '15 at 13:35

Rohit

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LINQ check if int? is in List C#

4 Answers4