iOS sort an NSArray of Time NSString's - ios

Question

I need to sort an NSArray containing time NSString's such as,
NSMutableArray *times = [[NSMutableArray alloc]initWithObjects:#"09:00 AM",#"07:30 AM",#"06:45 PM",#"05:00 PM",#"12:45 AM",#"12:45 PM",#"01:00 AM",#"01:15 PM", nil];
What I need is to sort the array in ascending order of time.
Is there any way to do such a thing?

Answer 1

NSMutableArray *times = [[NSMutableArray alloc]initWithObjects:#"09:00 AM",#"07:30 AM",#"06:45 PM",#"05:00 PM",#"12:45 AM",#"12:45 PM",#"01:00 AM",#"01:15 PM", nil];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"hh:mm a"];
NSArray *sortedTimes = [times sortedArrayUsingComparator:^NSComparisonResult(NSString *obj1, NSString *obj2)
{
NSDate *date1 = [dateFormatter dateFromString:obj1];
NSDate *date2 = [dateFormatter dateFromString:obj2];
return [date1 compare:date2];
}];
optimized version:
NSMutableArray *times = [[NSMutableArray alloc]initWithObjects:#"09:00 AM",#"07:30 AM",#"06:45 PM",#"05:00 PM",#"12:45 AM",#"12:45 PM",#"01:00 AM",#"01:15 PM", nil];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"hh:mm a"];
NSMutableArray *dates = [NSMutableArray arrayWithCapacity:times.count];
for (NSString *timeString in times)
{
NSDate *date = [dateFormatter dateFromString:timeString];
[dates addObject:date];
}
[dates sortUsingSelector:#selector(compare:)];
NSMutableArray *sortedTimes = [NSMutableArray arrayWithCapacity:dates.count];
for (NSDate *date in dates)
{
NSString *timeString = [dateFormatter stringFromDate:date];
[sortedTimes addObject:timeString];
}

Answer 2

You can try this code:
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:#"hh:mm a"];
[times sortUsingComparator:^NSComparisonResult(NSString* obj1, NSString *obj2) {
NSDate *firstDate = [formatter dateFromString:obj1];
NSDate *secondDate = [formatter dateFromString:obj2];
return [firstDate compare:secondDate];
}];

Answer 3

As these are strings it will be sored as
01:15, 12:25, 05:00....
And they are not either NSDate.
So you need to do is that Create a parallel array having NSDate from these strings, sort the array, and extract these values.
While implementing I solved it by novice-way
NSMutableArray *times = [[NSMutableArray alloc]initWithObjects:#"09:00 AM",#"07:30 AM",#"06:45 PM",#"05:00 PM",#"12:45 AM",#"12:45 PM",#"01:00 AM",#"01:15 PM", nil];
NSMutableArray *dates=[NSMutableArray new];
NSDateFormatter *dateFormatter=[NSDateFormatter new];
[dateFormatter setDateFormat:#"hh:mm a"];
for (NSString *stringDate in times) {
NSDate *date=[dateFormatter dateFromString:stringDate];
[dates addObject:date];
}
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:#"self" ascending:YES];
NSArray *descriptors = [NSArray arrayWithObject: descriptor];
NSArray *reverseOrder = [dates sortedArrayUsingDescriptors:descriptors];
[times removeAllObjects];
for (NSDate *date in reverseOrder) {
NSString *string=[dateFormatter stringFromDate:date];
[times addObject:string];
}
NSLog(#"%#",times);

Answer 4

For NSDate Comparison use this:
+ (BOOL)isDate:(NSDate *)date1 smallerThanAnotherDate:(NSDate *)date2
{
NSDate* enddate = date1;
NSDate* currentdate = date2;
NSTimeInterval distanceBetweenDates = [enddate timeIntervalSinceDate:currentdate];
double secondsInMinute = 60;
NSInteger secondsBetweenDates = distanceBetweenDates / secondsInMinute;
if (secondsBetweenDates <= 0)
return YES;
else
return NO;
}
So If you do not want to convert your hours to NSDate do this alone it works for me
NSArray *sortedTimes = [times sortedArrayUsingSelector:#selector(localizedStandardCompare:)];