Sort values of NSMutableDictionary alphabetically

Question

I have NSMutableDictionary with Integers as Key and NSString as Values for example:

Key -- Value

1 -- B

2 -- C

3 -- A

Now i want to Sort NSMutableDictionary alphabetically using values. So i want my dictionary to be like : Key(3,1,2)->Value(A,B,C). How can i perform this?

Look at this http://jomnius.blogspot.in/2011/12/how-to-sort-nsdictionary.html — Jitendra, Mar 24 '14 at 07:16
possible duplicate: http://stackoverflow.com/questions/9708742/getting-nsdictionary-keys-sorted-by-their-respective-values — NeverHopeless, Mar 24 '14 at 07:16

score 3 · Accepted Answer · answered Mar 24 '14 at 07:20

From Apple docs: https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Collections/Articles/Dictionaries.html#//apple_ref/doc/uid/20000134-SW4

Sorting dictionary keys by value:

NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:
    [NSNumber numberWithInt:63], @"Mathematics",
    [NSNumber numberWithInt:72], @"English",
    [NSNumber numberWithInt:55], @"History",
    [NSNumber numberWithInt:49], @"Geography",
    nil];

NSArray *sortedKeysArray =
    [dict keysSortedByValueUsingSelector:@selector(compare:)];
// sortedKeysArray contains: Geography, History, Mathematics, English

Blocks ease custom sorting of dictionaries:

NSArray *blockSortedKeys = [dict keysSortedByValueUsingComparator: ^(id obj1, id obj2) {

     if ([obj1 integerValue] > [obj2 integerValue]) {
          return (NSComparisonResult)NSOrderedDescending;
     }

     if ([obj1 integerValue] < [obj2 integerValue]) {
          return (NSComparisonResult)NSOrderedAscending;
     }
     return (NSComparisonResult)NSOrderedSame;
}];

Quite interesting, I guess the only meaningful way to store the 'sorted' dictionary is storing in an array, as dictionaries by their very nature have no order, right? — Woodstock, Mar 24 '14 at 07:27
@JohnWoods - Correct, an `NSDictionary` is an unordered collection of key. value pairs. — CRD, Mar 24 '14 at 07:45
Yes, NSDictionary is hash table based. When you say, 'sorted' dictionary, it's the 'keys' which you need in order to get their values. — Ajith Renjala, Mar 24 '14 at 07:53

score 2 · Answer 2 · answered Mar 24 '14 at 07:22

try this logic

  NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"B",@"B",@"A",@"A",@"C",@"C", nil];
    NSMutableArray *sortedArray = [NSMutableArray arrayWithArray:[dict allKeys]];
    [sortedArray sortUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
    for (NSString *key in sortedArray) {
        NSLog(@"%@",[dict objectForKey:key]);
    }

Sort values of NSMutableDictionary alphabetically

2 Answers2