I’m yet another newbie trying to use some simple test apps to get a better understanding of Cocoa.. I have an NSMutableArray of Transaction objects {Date, Name, Account, Amount}, which is manipulated with an NSArrayController/NSTableView in a Document based app.

I am trying to do some calculations in my MyDocument.m, and I’m a bit confused. I have found several examples on sorting Cocoa objects like NSStrings, NSNumbers, etc. But, I have those in my Transaction objects. Do I need to create a ‘compare’ method for my class, or can I tell sort to use the NSDate/date element in my transaction object?

I believe I would use this: [transactions sortUsingSelector:@selector(compare:)];

If I can tell it to use the ‘date’ in each object.

Thanks for any tips..

Unfortunately, Cocoa doesn’t make this simple, but it’s not that hard. Basically, you have to use NSSortDescriptor. –JediKnil

NSSortDescriptor *sortByDate = [[NSSortDescriptor alloc] initWithKey:@”date” ascending:NO]; // or YES NSArray *descriptors = [[NSArray alloc] initWithObjects:sortByDate, nil]; [transactions sortUsingDescriptors:descriptors]; [descriptors release]; [sortByDate release];

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Thanks for the reply, JediKnil!