NSSortDescriptor sort with number as string? - objective-c

Question

Got a an Array full of dictionary likes this:
(
{ order = "10";
name = "David"
};
{ order = "30";
name = "Jake";
};
{ order = "200";
name = "Michael";
};
)
When i'm using NSSortDescriptor like the code below it only sorts regarding to the first char so 200 is lower then 30. I can of course change the "order" object into a NSNumber instead of string and it would work. But is there a way to sort a string as int values without changing the source object?
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:#"norder" ascending:YES];
[departmentList sortUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];
Update:
Thanks to bandejapaisa.
Here is the a working version for iOS 5 (Xcode where compalining).
NSArray *sortedArray;
sortedArray = [departmentList sortedArrayUsingComparator:(NSComparator)^(id a, id b) {
NSNumber *num1 = [NSNumber numberWithInt:[[a objectForKey:#"norder"] intValue]];
NSNumber *num2 = [NSNumber numberWithInt:[[b objectForKey:#"norder"] intValue]];
return [num1 compare:num2];
}];
departmentList = [sortedArray mutableCopy];

Answer 1

Using a NSNumber is overkill. You can save yourself a lot of overhead by doing the following:
NSArray *sortedArray = [someArray sortedArrayUsingComparator:^(id obj1, id obj2) {
return (NSComparisonResult) [obj1 intValue] - [obj2 intValue];
}];

Answer 2

Maybe sort using a comparator instead, or one of the other sorting methods:
NSArray *sortedArray = [someArray sortedArrayUsingComparator:^(id obj1, id obj2) {
NSNumber *num1 = [NSNumber numberWithInt:[obj1 intValue]];
NSNumber *num2 = [NSNumber numberWithInt:[obj2 intValue]];
return (NSComparisonResult)[rank1 compare:num2];
}];

Answer 3

All the above methods need good knowledge in basics to implement, but for the freshers i suggest the most simplest way is to use the native block method, hope this helps
NSArray* sortedArr =[fetchResults sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
int aValue = [[a valueForKey:#"subgroupId"] intValue];
int bValue = [[b valueForKey:#"subgroupId"] intValue];
return aValue>bValue; }];
Happy Coding...