On Jun 6, 2008, at 2:26 PM, Andrew Merenbach wrote:
Quoting Ken Thomases <[EMAIL PROTECTED]>:
On Jun 6, 2008, at 3:43 AM, George Stuart wrote:
NSSortDescriptor *desc = [[NSSortDescriptor alloc]
initWithKey:nil ascending:NO
selector:@selector(localizedCompare:)];
NSArray *sortedArray = [unsortedArray sortedArrayUsingDescriptors:
[NSArray arrayWithObject:desc]];
[desc release];
That seems to work just fine... but I'm worried. I "guessed" at
using the key of "nil" since I want the actual objects in the
array to be the target for the @selector. Is it a fluke that
this works? I don't want to rely on undefined behavior.
Hmm. Good question. You could use @"description" as the key to
eliminate the uncertainty. Or maybe @"self".
Cheers,
Ken
Hi,
This may not be an option in every case, but would making a
"wrapper" class for your strings work? It'd just be a basic class
with an accessor/property and a corresponding ivar that would then
be the sort key.
Cheers,
Andrew
Thanks very much for the responses! I'm leaning away from writing a
wrapper as I'd rather try and leverage the base objects as much as
possible. Adding a wrapper will add complexity -- every place a
string is inserted needs to be sure to first wrap the NSString in my
custom wrapper. It's a minor change, but would like to avoid this if
possible.
The suggestion of using a keyPath of @"self" presents another question:
1) I assume NSSortDescriptor is using valueForKeyPath:, which in
turns calls valueForKey: some number of times, to get the object for
the keyPath I specified. Is it defined behavior that sending an
object valueForKey:@"self" will return the object itself? I guess
this is ultimately the same as my original question, "is it defined
behavior that sending an object valueForKey:nil will return the object
itself?"
As for using a keyPath of @"description", I think this might be the
best way for NSString. I completely forgot about this option. The
docs say:
Returns the receiver.
- (NSString *)description
Duh... That's precisely what I need :).
Thanks,
George
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