Question

I have something like this:

@interface Person : NSObject
{
  NSString *fname;
  NSString *lname;
}

NSString *keys = @"a","a","b","b","b"....";
for(NSString *key in keys)
{
    Person *newPerson; //alloc new person
    [myMutableDictionary setValue:newPerson forKey:key];
}

The above code will override the value with same key since NSDictionary doesn’t allow duplicate keys. How can I do this?
I can do the above code by NSMutableArray, as in [array addObject:newPerson]; but it takes longer to fetch for (Key,value) as opposed to NSDictionary? My data is about 400,000 items, Any idea on how to do this efficiently? I need to load it once and do many fetches on it – No coreData, I tried it, its slow.

Answer 1

If you use an NSMutableArray as a key you can add multiple Person objects for the same key.

NSString *keys = @"a","a","b","b","b", ...;
for(NSString *key in keys)
{
    Person *newPerson; //alloc new person
    NSMutableArray *people;
    if(!(people = [myMutableDictionary objectForKey:key]))
    {
        people = [NSMutableArray array];
        [myMutableDictionary setValue:people forKey:key];
    }

    [people addObject:newPerson];
}