Question

I have an NSDictionary object with 200 objects and 10 keys.
How do I return a subset and would it have to go to another NSDictionary or to an NSArray?

thanks

Answer 1

The objects stored in NSDictionary are stored by key, so if you only have 10 keys, you can only have 10 objects. To illustrate:

NSMutableDictionary* dict = [[NSMutableDictionary alloc] init];

[dict setObject:@"test1" forKey:@"key"]; // dict["key"] = "test1"
[dict setObject:@"test2" forKey:@"key"]; // dict["key"] = "test2"
[dict setObject:@"test3" forKey:@"key"]; // dict["key"] = "test3"

NSLog(@"%@", [dict objectForKey:@"key"]); // will print "test3"

[dict release];

If you add something to the dictionary with the same key as an existing object, the old object is removed and the new one is added instead.

If you want a dictionary that stores 10 sets of objects per key, you would have to store NSArray objects in your dictionary:

[dict setObject:someArray forKey:@"someKey"];