How to sort a mutable array with reference to Date which is saved as "object for key" in iphone?

Question

I am new to iphone development .I have mutable array recent in which the values such as title,date,url and summary are stored as " object for key".The keys are myurl,mudate,mytitle,mysummary.I want to sort that mutable array in reference to date and print all the values according to that..How can i achieve that?Please help me out.Thanks.

            [item setObject:currentTitle forKey:@"title"];
            [item setObject:currentLink forKey:@"link"];
            [item setObject:currentSummary forKey:@"description"];
            [item setObject:currentDate forKey:@"pubDate"];//
            [item setObject:currentImage forKey:@"imagePath"];

            [recent addObject:[item copy]];

All are xml parsed contents.

Answer 1

So I'm guessing you have an array of dictionaries. There are a couple ways to do this, but the one I recommend is using NSSortDescriptor. You'll want to do something like this:

//myArray is the name of the your array
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:@"mydate" ascending:YES]; // If you want newest at the top, pass NO instead.
[myArray sortUsingDescriptor:descriptor]; // This will modify myArray. To return a new array and leave the original untouched, use -sortedArrayUsingDescriptor:.
[descriptor release];
NSLog(@"%@", myArray); // Print.

If you you have your dates as NSDate objects already, this will work fine. If not, you'll either need to loop through the array and parse the dates beforehand, or use the initWithKey:ascending:selector: method of NSSortDescriptor, which allows you to define a custom comparison method.

Answer 2

Take a look at NSMutableArray's sortUsingComparator: and NSComparator.