title: Objective-C: Sort keys of NSDictionary based on dictionary entries
body: <p>OK so I know that dictionaries can't be sorted. But, say I have <code>NSMutableArray *keys = [someDictionary allKeys];</code> Now, I want to sort those keys, based on the corresponding values in the dictionary (alphabetically). So if the dictionary contains <code>key=someString</code>, then I want to sort <code>keys</code> based on the strings they correspond to. I think its some application of <code>sortUsingComparator</code> but its a little out of my reach at this point. </p>