Getting NSDictionary keys sorted by their respective values

Question

I have an NSMutableDictionary with integer values, and I\'d like to get an array of the keys, sorted ascending by their respective values. For example, with thi

Answer 1

Here i have done something like this:

NSMutableArray * weekDays = [[NSMutableArray alloc] initWithObjects:@"Sunday",@"Monday",@"Tuesday",@"Wednesday",@"Thursday",@"Friday",@"Saturday", nil];
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
NSMutableArray *dictArray = [[NSMutableArray alloc] init];

for(int i = 0; i < [weekDays count]; i++)
{
    dict = [NSMutableDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:i],@"WeekDay",[weekDays objectAtIndex:i],@"Name",nil];
    [dictArray addObject:dict];
}
NSLog(@"Before Sorting : %@",dictArray);

@try
{
    //for using NSSortDescriptor
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"WeekDay" ascending:YES];
    NSArray *descriptor = @[sortDescriptor];
    NSArray *sortedArray = [dictArray sortedArrayUsingDescriptors:descriptor];
    NSLog(@"After Sorting : %@",sortedArray);

    //for using predicate
    //here i want to sort the value against weekday but only for WeekDay<=5
   int count=5;
    NSPredicate *Predicate = [NSPredicate predicateWithFormat:@"WeekDay <=%d",count];
    NSArray *results = [dictArray filteredArrayUsingPredicate:Predicate];

    NSLog(@"After Sorting using predicate : %@",results);
}
@catch (NSException *exception)
{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Sorting cant be done because of some error" message:[NSString stringWithFormat:@"%@",exception] delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
    [alert setTag:500];
    [alert show];
    [alert release];
}