macOS Sorting NSMutableArray with NSDictionary inside

[alexanderl]

Hi All!
(I have to add that Im new to ObjC dev)

I have a NSMutableArray that contains NSDictionary objects, which each contain an object and a float (NSNumber).

Now I want to sort the Array based on the float... How do I do that?

I'm trying with sortUsingSelector: but I dont get it to work....

Thanks for your help!
alex

 

[caveman_uk]

Use an NSSortDescriptor.

 

[alexanderl]

Thanks caveman_uk!

Ok here is what I got so far (and what doesnt work)

[resultsForThisTestData addObject:[NSDictionary dictionaryWithObjectsAndKeys:dpp, @"DataPoint",
[NSNumber numberWithFloat:distance],@"Distance",nil]];


NSSortDescriptor * sortByDistance = [[[NSSortDescriptor alloc] initWithKey"Distance" ascending:TRUE] autorelease];

[resultdata initWithArray:[results sortedArrayUsingDescriptors:[NSArray arrayWithObjects:sortByDistance, nil]]];

(hope that is all the code you need)

As I said, this doesnt work and I dont see why?!?!

Thanks!
Alex

 

[stackolee]

Check out the official documentation: http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/Collections/Articles/sortingFilteringArrays.html

This example helped me out:

NSSortDescriptor *lastDescriptor =

        [[[NSSortDescriptor alloc] initWithKey:LAST

                                   ascending:NO

                                   selector:@selector(localizedCaseInsensitiveCompare:)] autorelease];

NSSortDescriptor *firstDescriptor =

    [[[NSSortDescriptor alloc] initWithKey:FIRST

                               ascending:NO

                               selector:@selector(localizedCaseInsensitiveCompare:)] autorelease];

NSArray *descriptors = [NSArray arrayWithObjects:firstDescriptor, lastDescriptor, nil];

sortedArray = [array sortedArrayUsingDescriptors:descriptors];