Sorting array(NSArray) in descending order

Question

I have a array of NSString objects which I have to sort by descending.

Since I did not find any API to sort the array in descending order I approached by following way.

I wrote a category for NSString as listed bellow.

- (NSComparisonResult)CompareDescending:(NSString *)aString {      NSComparisonResult returnResult = NSOrderedSame;      returnResult = [self compare:aString];      if(NSOrderedAscending == returnResult)         returnResult = NSOrderedDescending;     else if(NSOrderedDescending == returnResult)         returnResult = NSOrderedAscending;      return returnResult; } 

Then I sorted the array using the statement

NSArray *sortedArray = [inFileTypes sortedArrayUsingSelector:@selector(CompareDescending:)]; 

Is this right solution? is there a better solution?

Answer 1

You can use NSSortDescriptor:

NSSortDescriptor* sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:nil ascending:NO selector:@selector(localizedCompare:)]; NSArray* sortedArray = [inFileTypes sortedArrayUsingDescriptors:@[sortDescriptor]]; 

Here we use localizedCompare: to compare the strings, and pass NO to the ascending: option to sort in descending order.

Answer 2

or simplify your solution:

NSArray *temp = [[NSArray alloc] initWithObjects:@"b", @"c", @"5", @"d", @"85", nil]; NSArray *sortedArray = [temp  sortedArrayUsingComparator:                         ^NSComparisonResult(id obj1, id obj2){                             //descending order                             return [obj2 compare:obj1];                              //ascending order                             return [obj1 compare:obj2];                         }]; NSLog(@"%@", sortedArray);