What's the purpose of orderedDictionaryWithDictionary: method?

[zakdances]

Passing in an NSDictionary (which is unordered) to initialize an ordered dictionary doesn't sound valid. Shouldn't this method be replaced by a orderedDictionaryWithObjectsAndKeys: method so that an ordered dictionary can be initialized with multiple ordered keys/values?

[Marxon13]

If you look at the code, orderedDictionaryWithContentsOfDictionary: runs this method to create the ordered dictionary:

- (id)initWithContentsOfDictionary:(NSDictionary *)entrys
{
    self = [super init];
    if (self != nil) {
        keys = [[NSMutableArray alloc] initWithArray:entrys.allKeys];
        objects = [[NSMutableArray alloc] init];
        //Must loop through all keys, since order from NSDictionary is not defined.
        for (id key in keys) {
            [objects addObject:[entrys objectForKey:key]];
        }
        pairs = [[NSMutableDictionary alloc] initWithObjects:objects forKeys:keys];
    }
    return self;
}

This is valid because I first copy over the array of keys. I then iterate through all the keys to create the array of objects. Creating the ordered pairs of keys and objects. If the code was:

- (id)initWithContentsOfDictionary:(NSDictionary *)entrys
{
    self = [super init];
    if (self != nil) {
        keys = [[NSMutableArray alloc] initWithArray:entrys.allKeys];
        objects = [[NSMutableArray alloc] initWithArray:entrys.allObjects];
    }
    return self;
}

Then there will be a problem, since the order of keys may not match the order of objects in the NSDictionary.

[zakdances]

Understood.