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Re: Using NSSortDescriptor to reverse sort an NSArray containing NSString objects



On Jun 6, 2008, at 4:16 PM, Adam R. Maxwell wrote:

On Friday, June 06, 2008, at 02:07PM, "George Stuart" <email@hidden > wrote:

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 always use self as the key path in cases like this, since - [NSObject self] is documented to return the receiver.

And, to complete the picture, the documentation for valueForKey: describes how that method obtains the value for the key. The first step in its search for key @"self" would be to look for the method named "self".



It has the advantage of working with objects other than strings.

Well, so does -description. ;) It just gives a different thing. That is, -self always returns the receiver, while -description only returns the receiver for an NSString, but always returns something (a string) that may be useful for a given purpose (possibly even sorting).


Cheers,
Ken
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References: 
 >Using NSSortDescriptor to reverse sort an NSArray containing NSString objects (From: George Stuart <email@hidden>)
 >Re: Using NSSortDescriptor to reverse sort an NSArray containing NSString objects (From: Ken Thomases <email@hidden>)
 >Re: Using NSSortDescriptor to reverse sort an NSArray containing NSString objects (From: Andrew Merenbach <email@hidden>)
 >Re: Using NSSortDescriptor to reverse sort an NSArray containing NSString objects (From: George Stuart <email@hidden>)
 >Re: Using NSSortDescriptor to reverse sort an NSArray containing NSString objects (From: "Adam R. Maxwell" <email@hidden>)



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