More LINQ Madness

Posted By: Curt Nichols | Nov 30th, 2007 @ 6:11 PM
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Comments: 2 | Views: 1321
#Nov 30th, 2007 @ 6:11 PM
Curt Nichols
Curt Nichols
No Silver Bullet
I had a need for something like this today, thought I'd post it as a puzzle-

Using LINQ, select the members of set A that are not in set B:

    var setA = new List<string>() { "a", "c", "e", "b", "d", "f" };
    var setB = new List<string>() { "f", "c", "a" };

Smiley

I have a solution that I'll post later.

#Nov 30th, 2007 @ 6:57 PM
Curt Nichols
Curt Nichols
No Silver Bullet
JChung2006 wrote:


Ha ha! Oh, man, that's way better than mine. Except():

    var m in setA.Except(setB);

Here was my original, which is way too much "SQL-think." I've read that you can't get all SQLy on LINQ to Objects, but I haven't internalized all the extension methods yet, so I stuck with what I knew:

    // Don't try this at home!
    var missing =
        // Select only where there's no match.
        from match in
            // Outer join.
            from a in setA
            join b in setB on a equals b into matches
            from b in matches.DefaultIfEmpty()
            select new { a, b }
        where match.b == null
        select match.a;

Clearly the shorter version is the way to go. Thanks! Smiley
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