linq where clause when id is in an array

Question

I have a method which should return list of Users if the UserId is in an array. The array of UserIds is passed to the method.

I'm not sure how to write ..where userid in array?

below in ids[] is clearly not correct.

public List<User> GetUsers(int[] ids)
{
   return Users.Values.Where(u => u.UserID in ids[]).ToList();
}

Any ideas how to correct that?

Thanks,

the annoyances of typing up a reply to see someones already posted the same thing and a few people are already voting it.. so I deleted it — BugFinder, Mar 07 '16 at 14:14
@BugFinder This is an old problem which has its own name ([Fastest Gun in the West](http://meta.stackexchange.com/q/9731/175984)). — Sergey Kalinichenko, Mar 07 '16 at 14:16
Thanks :) I just hate to see 2 answers the same, its pointless.. even if both are right. — BugFinder, Mar 07 '16 at 14:16
Possible duplicate of [Where IN clause in LINQ](http://stackoverflow.com/questions/959752/where-in-clause-in-linq) — MakePeaceGreatAgain, Mar 07 '16 at 14:23

score 26 · Accepted Answer · edited Mar 07 '16 at 14:14

26

You can try something like that :

public List<User> GetUsers(int[] ids)
{
    return Users.Values.Where(u => ids.Contains(u.UserID)).ToList();
}

edited Mar 07 '16 at 14:14

Thomas Ayoub

answered Mar 07 '16 at 14:13

Quentin Roger

score 5 · Answer 2 · edited Jun 09 '20 at 21:25

5

Alternatively to Quentins answer, use this:

public List<User> GetUsers(int[] ids)
{
    return Users.Values.Where(u => ids.Any(x => x == u.UserID)).ToList();
}

edited Jun 09 '20 at 21:25

B--rian

answered Mar 07 '16 at 14:19

2 Answers2