Linq select from list where property matches a condition

Question

I have an collection of Videos who have a field typeidentifier that tells me if a video is a trailer, clip or interview.

I need to put them in 3 seperate collections.

var trailers = myMediaObject.Videos.Where(type => type.TypeIdentifier == 1);
var clips = myMediaObject.Videos.Where(type => type.TypeIdentifier == 2);
var interviews = myMediaObject.Videos.Where(type => type.TypeIdentifier == 3);

Is there a more efficient way of doing this? I love using Linq here though.

Answer 1

How about:

var lookup = myMediaObject.Videos.ToLookup(type => type.TypeIdentifier);
var trailers = lookup[1];
var clips = lookup[2];
var interviews = lookup[3];

Note that this will materialize the results immediately, whereas your first version didn't. If you still want deferred execution, you might want to use GroupBy instead - although that will be slightly trickier later on. It really depends what you need to do with the results.