Sort Array of Dictionaries by NSDate

Question

I have an array of dictionaries. Within each dictionary, there is a a key dateOfInfo (an NSDate) and several other things. I want to sort the array

Answer 1

You can sort using NSSortDescription, e.g.

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey: @"dateOfInfo" ascending: NO];
NSArray *sortedArray = [array sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
[sortDescriptor release];

You can also use the method

- (NSArray *)sortedArrayUsingFunction:(NSInteger (*)(id, id, void *))comparator context:(void *)context

Answer 2

The basic bubble sorting algorithm would work. In this case you need to loop through your array, use valueForKey message on [array objectAtIndex:] to get the NSDate values. For comparing dates see this post . So if you are sorting in ascending order of date, just add the object with the lower date (remember bubble sort comparisons?) to an array which will hold your sorted result.

Answer 3

try like this,

            NSDateFormatter *fmtDate = [[NSDateFormatter alloc] init];
             [fmtDate setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss"];
             NSComparator compareDates = ^(id string1, id string2)
             {
                 NSDate *date1 = [fmtDate dateFromString:string1];
                 NSDate *date2 = [fmtDate dateFromString:string2];

                 return [date1 compare:date2];
             };
             NSSortDescriptor * sortDesc1 = [[NSSortDescriptor alloc] initWithKey:@"StartTime" ascending:YES comparator:compareDates];
             [youArray sortUsingDescriptors:@[sortDesc1]];