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Editorial Team
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Asked: 2026-05-14T04:08:42+00:00

arr = [[NSMutableArray alloc]init]; [arr addObject:[NSNumber numberWithInt:4]]; [arr addObject:[NSNumber numberWithInt:45]]; [arr addObject:[NSNumber numberWithInt:23]]; [arr

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arr = [[NSMutableArray alloc]init];
[arr addObject:[NSNumber numberWithInt:4]];
[arr addObject:[NSNumber numberWithInt:45]];
[arr addObject:[NSNumber numberWithInt:23]];
[arr addObject:[NSNumber numberWithInt:12]];
NSLog(@"The avg = %@", [arr valueForKeyPath:@"@avg.intValue"]);

This code works fine, but why? valueForKeyPath:@"@avg.intValue" is requesting (int) from each NSNumber, but we are outputting a %@ string in the log. If i try to output a decimal %d i get a number that possibly is a pointer to something. Can somebody explain why the integers become NSNumbers when i call the @avg operator?

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1 Answer

  1. Editorial Team

    valueForKeyPath: must return an object (its return type is id), so you get an NSNumber or NSValue (I’m not sure which; it depends on whether the intValue gives an int or NSNumber, and (if the former) how the result is bundled back into an object), despite the intValue. It’s the same reason you can’t store non-objects in collections.

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