NSMutableDictionary does not sort correctly - iphone

Question

Let i have unsorted NSMutableDictionary
{
A = "3";
B = "2";
C = "4";
}
And i need result to be like:
{
B = "2";
A = "3";
C = "4";
}
How can i achieve this result in objective c.
A simple code implementation will be appreciated.

Answer 1

Not possible with an NSMutableDictionary, it is not a sorted structure. You will have to turn it into an NSArray and then sort that. You will then not have a dictionary structure.

Answer 2

You can not sort NSMutableDictionary by value as #joe and #mavrick3 answer. However if you change there keys and values to NSArray you can do it..
Here is simple implementation..
NSMutableDictionary *results; //dictionary to be sorted
NSMutableDictionary *results; //dict to be sorted
NSArray *sortedKeys = [results keysSortedByValueUsingComparator: ^(id obj1, id obj2) {
if ([obj1 integerValue] > [obj2 integerValue])
return (NSComparisonResult)NSOrderedDescending;
if ([obj1 integerValue] < [obj2 integerValue])
return (NSComparisonResult)NSOrderedAscending;
return (NSComparisonResult)NSOrderedSame;
}];
NSArray *sortedValues = [[results allValues] sortedArrayUsingSelector:#selector(compare:)];
//Descending order
for (int s = ([sortedValues count]-1); s >= 0; s--) {
NSLog(#" %# = %#",[sortedKeys objectAtIndex:s],[sortedValues objectAtIndex:s]);
}
//Ascending order
for (int s = 0; s < [sortedValues count]; s++) {
NSLog(#" %# = %#",[sortedKeys objectAtIndex:s],[sortedValues objectAtIndex:s]);
}

Answer 3

You can try this to sort your Dictionary.
NSMutableDictionary *tmpDict = [NSMutableDictionary dictionaryWithObjectsAndKeys:#"6",#"A",#"3",#"B",#"5",#"C",#"2",#"D",#"21",#"F",#"20",#"G",nil];
NSArray *sortedArray = [tmpDict keysSortedByValueUsingComparator:^NSComparisonResult(id obj1,id obj2){
return [obj1 compare:obj2 options:NSNumericSearch];
}];
NSLog(#"Sorted = %#",sortedArray);

Answer 4

NSDictionaryas well as NSMutableDictionary cannot be sorted by value. You can only use a NSArray to sort them. But you have to this with your own code and you won't get the same output as you want.

Answer 5

This is the simplest way to do this
NSArray *arr = [NSArray arrayWithObjects:#"2", #"4", #"1", nil];
NSArray *sorted = [arr sortedArrayUsingSelector:#selector(compare:)];
NSLog(#"Pre sort : %#", arr);
NSLog(#"After sort : %#", sorted);
If you have f.ex. array of dictionary (or model objects), you could do this :
NSDictionary *dict1 = [NSDictionary dictionaryWithObject:#"Mannie" forKey:#"name"];
NSDictionary *dict2 = [NSDictionary dictionaryWithObject:#"Zannie" forKey:#"name"];
NSDictionary *dict3 = [NSDictionary dictionaryWithObject:#"Cannie" forKey:#"name"];
NSArray *peopleIKnow = [NSArray arrayWithObjects:dict1, dict2, dict3, nil];
NSSortDescriptor *sorty = [NSSortDescriptor sortDescriptorWithKey:#"name" ascending:YES];
NSArray *results = [peopleIKnow sortedArrayUsingDescriptors:[NSArray arrayWithObject:sorty]];
NSLog(#"Before : %#", peopleIKnow);
NSLog(#"After : %#", results);