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objective-csortingnsarraynsdictionary

NSDictionary to ordered NSArray


I am on OSX, objective-c not iOS. I have an NSDictionary like that

NSDictionary* dict = [NSDictionary alloc initWithObjectsAndKeys: 
                @"valueC", @"key3",
                @"valueA", @"key1",
                @"valueB", @"key2",
                nil];

When i call allKeys and allValues of NSDictionary, i get NSArrays. But each time the app runs, the order changes - because NSDictionary is an unordered collection.

What i need is an array that contains all values but ordered after keys, alphabetical, ascending like that:

@[@"valueA", @"valueB",@"valueC"]; //--> ordered after their keys key1,key2,key3

EDIT Basically i need the opposite of this method:

- keysSortedByValueUsingComparator: // -> valuesSortedByKeyUsingComparator:

Any help appreciated.


Solution

  • You can sort the keys alphabetically first:

       sortedKeyArray = [[mydict allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
    

    and enumerate through this sorted array:

    [sortedKeyArray enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        [sortedValueArray addObject:mydict[obj];
    }];
    

    Now you have the sorted value in sortedValueArray