On Feb 19, 2011, at 5:17 PM, Michael Crawford wrote:
> When I look inside the set, you will see that the value -1748299021286640132
> is in the set. However, when -containsObject is called, it returns NO.
Are you sure the objects you are dealing with are always NSNumbers? If one of
them is an NSString, containsObject: will fail.
On Feb 19, 2011, at 5:28 PM, Scott Ribe wrote:
> I'm pretty sure that, for instance, two calls to [NSNumber
> numberWithLongLong: 1] will produce two different objects, and though they
> may fall into the same hash bucket if the hash method uses the numeric value,
> they will still not be treated as the same object by -containsObject.
That would strike me as very odd, since it would imply that the two instances
aren't isEqual: to each other. (The containsObject: doc isn't explicit about
whether it uses isEqual: to test for membership, but I assume so since member:
does.)
I just did a quick test and confirmed that you do get two different instances
with the same hash, but they are in face isEqual: to each other and hence their
presence in a set is detected, as I would expect.
NSNumber *one = [NSNumber numberWithLongLong:1];
NSNumber *another = [NSNumber numberWithLongLong:1];
NSSet *set = [NSSet setWithObject:another];
NSLog(@"+++ one %p, hash = %ld -- another %p, hash = %ld -- is eq = %d,
contains one = %d, contains another = %d",
one, [one hash], another, [another hash], [one isEqual:another], [set
containsObject:one], [set containsObject:another]);
--Andy
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