You can do this using Key Value Coding, specifically using the collection operators like @distinctUnionOfSets etc.
-Steven On Wed, Feb 10, 2010 at 9:11 PM, Jens Alfke <j...@mooseyard.com> wrote: > > On Feb 10, 2010, at 1:45 PM, Trygve Inda wrote: > > > iTunes seems to do this with the column browser... Eg when you select > > "Classic Rock", it pulls up a list of Artists without duplicates in the > > list... And does it very fast. > > But keep in mind that iTunes is a Carbon app, not Cocoa. > > > It seems like a Predicate is working here... When one clicks "Classic > Rock", > > that is added to the predicate as Genre="Classic Rock", but then how does > it > > extract the list of Artists from the master array since it doesn't want > > duplicates? > > You're asking about iTunes' implementation, which we have no idea about. It > seems to use some kind of custom database. What you're describing is a > typical sort of database query (in SQL it would be like "select distinct > artist from ..."). > > At a low level, in your code you could use an NSMutableSet to collect > together the artist results, which would remove duplicates. I'm sure this > would get awkward to work with, though. > > Basically I think you're running into the limitations of your very simple > data structure. You could come up with something more complex, or you could > start using CoreData and let it manage the data storage and querying for > you. > > —Jens_______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/cocoa-dev/steven.degutis%40gmail.com > > This email sent to steven.degu...@gmail.com > -- Steven Degutis http://www.thoughtfultree.com/ http://www.degutis.org/ _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
