If you're just sorting an array of NSNumbers, you can sort them with 1 call:
[arrayToSort sortUsingSelector: @selector(compare:)];
That works because the objects in the array (NSNumber objects) implement the compare method. You could do the same thing for NSString objects, or even for an array of custom data objects that implement a compare method.
Here's some example code using comparator blocks. It sorts an array of dictionaries where each dictionary includes a number in a key "sort_key".
#define SORT_KEY @\"sort_key\"
[anArray sortUsingComparator:
^(id obj1, id obj2)
{
NSInteger value1 = [[obj1 objectForKey: SORT_KEY] intValue];
NSInteger value2 = [[obj2 objectForKey: SORT_KEY] intValue];
if (value1 > value2)
{
return (NSComparisonResult)NSOrderedDescending;
}
if (value1 < value2)
{
return (NSComparisonResult)NSOrderedAscending;
}
return (NSComparisonResult)NSOrderedSame;
}];
The code above goes through the work of getting an integer value for each sort key and comparing them, as an illustration of how to do it. Since NSNumber objects implement a compare method, it could be rewritten much more simply:
#define SORT_KEY @\"sort_key\"
[anArray sortUsingComparator:
^(id obj1, id obj2)
{
NSNumber* key1 = [obj1 objectForKey: SORT_KEY];
NSNumber* key2 = [obj2 objectForKey: SORT_KEY];
return [key1 compare: key2];
}];
or the body of the comparator could even be distilled down to 1 line:
return [[obj1 objectForKey: SORT_KEY] compare: [obj2 objectForKey: SORT_KEY]];
I tend to prefer simple statements and lots of temporary variables because the code is easier to read, and easier to debug. The compiler optimizes away the temporary variables anyway, so there is no advantage to the all-in-one-line version.
