NSMutableDictionary with single key holding many values in Objective-C programming

Question

Please tell me how can we have multiple values for the same key in NSMutableDictionary?

When I use the below approach, the values are being replaced with the recent one.

In my case:

[dictionary setObject:forename forKey:[NSNumber numberWithint:code]];
[dictionary setObject:surname forKey:[NSNumber numberWithint:code]];
[dictionary setObject:reminderDate forKey:[NSNumber numberWithint:code]];

When I view the contents of the dictionary, I get only the reminderDate for key code. Here, the code is same for all values. How do I avoid forename and surname being replaced by plannedReminder.

Thank You!

Answer 1

It seems like you are using code as the key and you want to represent multiple values based on code. In that case, you should either:

1. Abstract all data associated with code into a separate class (perhaps called Person) and use instances of this class as values in the dictionary.

2. Use more than one layer of dictionaries:

   NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];
   
   NSMutableDictionary *firstOne = [NSMutableDictionary dictionary];
   [firstOne setObject:forename forKey:@"forename"];
   [firstOne setObject:surname forKey:@"surname"];
   [firstOne setObject:reminderDate forKey:@"reminderDate"];
   
   [dictionary setObject:firstOne forKey:[NSNumber numberWithInt:code]];
   
   // repeat for each entry.