NSDictionary without sorting in iOS - ios

Question

How to add and get the values from NSDictionary without key sorting?
NSDictionary is sorting the keys automatically.
How to get dictionary on added object format without sorting?
I have added the objects in below order.
NSDictionary *ScroesDic = [NSDictionary dictionaryWithObjectsAndKeys:#3,#"id_player",#100,#"shots[0][power]",#90,#"shots[0][precision]",#72,#"shots[1][power]",#27,#"shots[1][precision]",#23,#"shots[2][power]",#80,#"shots[2][precision]",#23,#"shots[3][power]",#80,#"shots[3][precision]",#23,#"shots[4][power]",#80,#"shots[4][precision]",#23,#"shots[5][power]",#80,#"shots[5][precision]",#23,#"shots[6][power]",#80,#"shots[6][precision]",#23,#"shots[7][power]",#80,#"shots[7][precision]",#23,#"shots[8][power]",#80,#"shots[8][precision]",#23,#"shots[9][power]",#80,#"shots[9][precision]",#23,#"shots[10][power]",#80,#"shots[10][precision]",#23,#"shots[11][power]",#80,#"shots[11][precision]",#23,#"shots[12][power]",#80,#"shots[12][precision]", nil];
NSLog(#"%#",ScroesDic);
But,the dictionary returns below order.
{
"id_player" = 3;
"shots[0][power]" = 100;
"shots[0][precision]" = 90;
"shots[10][power]" = 23;
"shots[10][precision]" = 80;
"shots[11][power]" = 23;
"shots[11][precision]" = 80;
"shots[12][power]" = 23;
"shots[12][precision]" = 80;
"shots[1][power]" = 72;
"shots[1][precision]" = 27;
"shots[2][power]" = 23;
"shots[2][precision]" = 80;
"shots[3][power]" = 23;
"shots[3][precision]" = 80;
"shots[4][power]" = 23;
"shots[4][precision]" = 80;
"shots[5][power]" = 23;
"shots[5][precision]" = 80;
"shots[6][power]" = 23;
"shots[6][precision]" = 80;
"shots[7][power]" = 23;
"shots[7][precision]" = 80;
"shots[8][power]" = 23;
"shots[8][precision]" = 80;
"shots[9][power]" = 23;
"shots[9][precision]" = 80;
}

Answer 1

NSDictionary is not meant to be sorted. You can get it sorted by getting all keys using allKeys and sorting that array to your liking. Then loop through this array and get the corresponding values.
Here is one way of doing it:
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:#"key" ascending:YES comparator:^(id obj1, id obj2) {
if (obj1 > obj2) {
return (NSComparisonResult)NSOrderedDescending;
}
if (obj1 < obj2) {
return (NSComparisonResult)NSOrderedAscending;
}
return (NSComparisonResult)NSOrderedSame;
}];
NSArray *sortedKeys = [[filteredDictionary allKeys] sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
NSMutableDictionary *orderedDictionary = [NSMutableDictionary dictionary];
for (NSString *index in sortedKeys) {
[orderedDictionary setObject:[filteredDictionary objectForKey:index] forKey:index];
}
filteredDictionary = orderedDictionary;
May it helps you.

Answer 2

Like an NSSet, the NSDictionary class represents an unordered
collection of objects; however, they associate each value with a key,
which acts like a label for the value.
You dont need to order the NSDictionary in anyway.That's make no sense. Because you are accessing the object by using the key not in any order.

Answer 3

By documentation, keys order in a NSDictionary is not defined:
allKeys
Returns a new array containing the dictionary’s keys.
(NSArray *)allKeys
Return Value
A new array containing the dictionary’s keys, or an empty array if the dictionary has no > entries.
Discussion
The order of the elements in the array is not defined.
If you want to keep a particular order of your keys, let's say the "insertion order" what you can do is subclass NSDictionary (difficult, as you should maintain the complex internal API coherent) or make a new class which contains internally a NSDictionary + NSArray to keep the insertion order of the keys, and then build a custom API similar to the NSDictionary one (but just a small subset of the methods you really need). E.g. of a mutable class:
#interface MyDictionary ()
#property (strong,nonatomic) NSMutableDictionary *internalDictionary;
#property (strong,nonatomic) NSMutableArray *internalArray;
#end
#implementation MyDictionary
-(id)init {
self = [super init];
if(self) {
_internalDictionary = [NSMutableDictionary new];
_internalArray = [NSMutableArray new];
}
}
-(void)setObject:(id)value forKey:(id)key {
_internalDictionary[key]=value;
// add key in array only if not already added yet
if(![_internalArray containsObject:key]) {
[_internalArray addObject:key];
}
}
#end