Question

I have a mutlidimensional NSDictionary, and am having problems adding an array to it. My dictionary structure looks like this: (taken by NSLogging the dictionary)

{
    Downloaded =     {
        017315 = "2013-01-16 11:26:33 +0000";
    };
    Projects =  (
        {
            Docs = { };
            "Last Downloaded" = "2013-01-16 10:16:05 +0000";
            "Project Name" = "Baring Australia Fund";
        }
    );
}

I am trying to add a new array to the “Docs” dictionary. The code I am using is

[[[[myDict objectForKey:@"Projects"] objectAtIndex:0] objectForKey:@"Docs"] setObject:[NSMutableArray array] forKey:@"test"];

This is failing with the following error

Terminating app due to uncaught exception ‘NSInvalidArgumentException’, reason: ‘-[__NSArrayM objectForKey:]: unrecognized selector sent to instance 0x7592df0’

If I try to add a Dictionary to the Docs key instead of an array using the code below, it works.

[[[[myDict objectForKey:@"Projects"] objectAtIndex:0] objectForKey:@"Docs"] setObject:[NSMutableDictionary dictionary] forKey:@"test"];

In addition, I am also able to add the new array to the first “Projects” array item, just not to the Docs object within it.

What am I doing wrong, and why is this not working?

Thanks

Answer 1

[[[myDict objectForKey:@"Projects"] objectAtIndex:0] objectForKey:@"Docs"] this is returning you an array.

And you are using setObject:forKey: in this array.

[someArray setObject: forKey:] is what your compiler see and throwing error.

EDIT:

I checked your code, it is fine. and the above error is coming from some other places.

I mimic-ed your code and it works fine. Have a look, what i tested:

 NSMutableDictionary *myDict=[NSMutableDictionary new];

NSMutableDictionary *downloadedDict=[NSMutableDictionary dictionaryWithObject:@"2013-01-16 11:26:33 +0000" forKey:@"017315"];
[myDict setObject:downloadedDict forKey:@"Downloaded"];

NSMutableDictionary *docsDict=[NSMutableDictionary new];
NSMutableDictionary *emptyDict=[NSMutableDictionary new];
[docsDict setObject:emptyDict forKey:@"Docs"];
[docsDict setObject:@"2013-01-16 10:16:05 +0000" forKey:@"Last Downloaded"];
[docsDict setObject:@"Baring Australia Fund" forKey:@"Project Name"];
NSMutableArray *projects=[NSMutableArray new];
[projects addObject:docsDict];


[myDict setObject:projects forKey:@"Projects"];

// NSLog(@"%@",mainDict);
//[[[[myDict objectForKey:@"Projects"] objectAtIndex:0] objectForKey:@"Docs"] setObject:[NSMutableDictionary dictionary] forKey:@"test"];
[[[[myDict objectForKey:@"Projects"] objectAtIndex:0] objectForKey:@"Docs"] setObject:[NSMutableArray array] forKey:@"test"];

NSLog(@"%@",myDict);