Objective-C: Sort keys of NSDictionary based on dictionary entries

Question

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

Answer 1

NSArray *keys = [someDictionary allKeys];
NSArray *sortedKeys = [keys sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
    NSString *first = [someDictionary objectForKey:a];
    NSString *second = [someDictionary objectForKey:b];
    return [first compare:second];
}];