How to get the largest value from NSArray containing dictionaries?

Question

How do you get the largest value from an NSArray with dictionaries?

Lets say I have NSArray containing dictionaries with keys "age", "name", etc. Now I want to get the record with the highest age. Is this possible with some KVC magic? Or do I have to iterate through and do it the "manual" way?

I've tried with something similar to this:

int max = [[numbers valueForKeyPath:@"@max.intValue"] intValue];

Answer 1

Unless "intValue" is a key in your dictionary the key path won't do much good.

If it is the max age you are after you should use @"@max.age" (on the dictionary) to get it. The same goes for any other key in your dictionary.

[myDictionary valueForKeyPath:@"@max.age"];

If numbers is an array of values you could use @"@max.self" as the key path to get the largest value.

[myArrayOfNumbers valueForKeyPath:@"@max.self"];

Answer 2

You're nearly there, you just need to specify the exact field you want from which you want the max value:

NSInteger max = [[numbers valueForKeyPath:@"@max.age"] integerValue];

I took the liberty to modify your ints to NSIntegers, just in case somebody wants to use this code on both iOS and OS X.