CODEWITHSUNDEEP
iphoneobjective-ciossortingnsmutablearray
ZeNewb
ZeNewb

Reputation: 435

Sorting mutable array by dictionary key

I have already looked through a few answers using the various sorting methods of NSMutableArray, but for some reason they are not working for me.

I am just trying to sort the mutable array which contains dictionaries by the Delay key within each dictionary. However, the "sorted" array is the exact same as the original array.

By the way, it works fine if I create a dummy mutable array and populate it with dictionaries containing numbers, but for some reason it won't sort this mutable array that I am initializing.

What am I doing wrong?

Here's my code:

playlistCalls = [[NSMutableArray alloc] initWithArray:[currentPlaylist objectForKey:@"Tunes"]];

NSLog(@"original %@", playlistCalls);

NSSortDescriptor *delay = [NSSortDescriptor sortDescriptorWithKey:@"Delay" ascending:YES];
[playlistCalls sortUsingDescriptors:[NSArray arrayWithObject:delay]];

NSLog(@"sorted %@", playlistCalls);

Here's the array containing the dictionaries:

2012-06-04 15:48:09.129 MyApp[57043:f503] original (
        {
        Name = Test Tune;
        Delay = 120;
        Volume = 100;
    },
        {
        Name = Testes;
        Delay = 180;
        Volume = 100;
    },
        {
        Name = Testing;
        Delay = 60;
        Volume = 100;
    }
)

2012-06-04 15:48:09.129 MyApp[57043:f503] sorted (
        {
        Name = Test Tune;
        Delay = 120;
        Volume = 100;
    },
        {
        Name = Testes;
        Delay = 180;
        Volume = 100;
    },
        {
        Name = Testing;
        Delay = 60;
        Volume = 100;
    }
)

Upvotes: 6

Views: 1130

Answers (2)

Joe
Joe

Reputation: 57169

The code above is fine when I use NSNumbers in my dictionary. That leads me to believe that the Delay value is stored as strings in your dictionary. What you will need to do then is sort by the strings integerValue.

NSSortDescriptor *delay = 
   [NSSortDescriptor sortDescriptorWithKey:@"Delay.integerValue" ascending:YES];

Upvotes: 8

Omar Abdelhafith
Omar Abdelhafith

Reputation: 21221

Please try the following, it worked with me

NSDictionary *dic;
NSMutableArray *arr = [[NSMutableArray alloc] init];

dic = [NSDictionary dictionaryWithObjectsAndKeys:
        [NSNumber numberWithInt:120], @"Delay",
        [NSNumber numberWithInt:100], @"Volume",
       nil];
[arr addObject:dic];

dic = [NSDictionary dictionaryWithObjectsAndKeys:
       [NSNumber numberWithInt:160], @"Delay",
       [NSNumber numberWithInt:100], @"Volume",
       nil];
[arr addObject:dic];

dic = [NSDictionary dictionaryWithObjectsAndKeys:
       [NSNumber numberWithInt:100], @"Delay",
       [NSNumber numberWithInt:100], @"Volume",
       nil];
[arr addObject:dic];

NSSortDescriptor *sortDesc = [[NSSortDescriptor alloc] initWithKey:@"Delay" ascending:YES];
[arr sortUsingDescriptors:[NSArray arrayWithObject:sortDesc]];

Upvotes: 1

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