It should work the way you've done it in a NSDictionary. Yes the numbers created by +numberWithUnsignedInteger: are distinct objects (normally, if I use low numbers they actually aren't, one of Cocoa's little optimizations I guess), however they compare as equal with isEqual: or isEqualToNumber:
NSDictionary uses isEqual: so it should find it with no issue. I just threw together a 10 line program which does that, puts an entry into a dictionary keyed on an NSNumber representation of an NSUInteger and gets it out with another distinct NSNumber of the same NSUInteger, it finds it. I did also test in that case that the two NSNumbers were distinct, they were. On 29-Oct-2010, at 7:29 PM, Graham Cox wrote: > I have a need to associate objects with an arbitrary unsigned integer, which > can be pretty much anything. I figured a dictionary with NSNumbers as keys > would be perfect, where the NSNumber is created using > +numberWithUnsignedInteger: > > Trouble is, each time I create the number, it's a new object even if it > contains a value NSNumber has seen before, so the lookup fails. > > So, I thought I'd just create suitable static NSNumbers, but I have the same > problem in another place, since I then need to know which static NSNumbers > I've allocated already to a given integer, which means looking them up. While > I could just add them to an array and conduct a linear search - for the > current situation efficiency isn't likely to be an issue - this solution > wouldn't scale very well if it ever needed to. > > Is there an obvious alternative I'm overlooking? > > --Graham > > > _______________________________________________ > > 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/rols%40rols.org > > This email sent to r...@rols.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
