How to sort Array of dates? [duplicate]

Question

I have a dates in Array like below and i want to sort it.

 NSMutableArray *arrDates =[[NSMutableArray alloc]init];
[arrDates addObject:@"24/01/2010"];
[arrDates addObject:@"15/05/2014"];
[arrDates addObject:@"04/03/2011"];
[arrDates addObject:@"30/05/2013"];
[arrDates addObject:@"11/10/2012"];

I tried with below code but am not getting what should i pass exactly as a Key here.

NSSortDescriptor *sortDis = [[NSSortDescriptor alloc] initWithKey:????? ascending:TRUE];
[arr sortUsingDescriptors:[NSArray arrayWithObject:sortDis]];

I passed self but its sorting only based on date(day).

I want to display result as below

and also i tried with below line

[arrDates sortUsingSelector:@selector(compare:)];

but no use. Please help.

like for (NSString *strDate in arrDates) { NSDateFormatter *formatter=[NSDateFormatter new]; [formatter setDateFormat:@"dd/MM/yyyy"]; NSDate *date=[formatter dateFromString:strDate]; [arr addObject:date]; } — Ganesh G
– Ganesh G, Commented Jun 4, 2013 at 11:38

trojanfoe · Accepted Answer · 2013-06-04 11:37:02Z

8

Store your data using the appropriate type, which for dates is NSDate and then you can use:

NSArray *sorted = [array sortedArrayUsingComparator:^NSComparisonResult(NSDate *date1, NSDate *date2) {
    return [date1 compare:date2];
}];

Which assumes array is an NSArray of NSDate objects.

answered Jun 4, 2013 at 11:37

trojanfoe

123k23 gold badges219 silver badges249 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

HAS Over a year ago

+1 Most efficient answer :)

Ramy Al Zuhouri Over a year ago

Also it has few lines of code.

Ganesh G Over a year ago

+1 @trojanfoe, this is best answer. If i have 100 obj then will it slow in this condition?

Groot Over a year ago

This would not be slow even if you had "...OVER 10 000!!!!"

Ganesh G Over a year ago

I am not getting Why the Date format is changing to 2009-10-01 this format?

|

Anupdas · Accepted Answer · 2013-06-04 11:37:33Z

4

Try

NSMutableArray *arrDates =[[NSMutableArray alloc]init];
[arrDates addObject:@"24/01/2010"];
[arrDates addObject:@"15/05/2014"];
[arrDates addObject:@"04/03/2011"];
[arrDates addObject:@"30/05/2013"];
[arrDates addObject:@"11/10/2012"];

NSDateFormatter *dateFormatter = [NSDateFormatter new];
[dateFormatter setDateFormat:@"dd/MM/yyyy"];
[arrDates sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
    NSDate *date1 = [dateFormatter dateFromString:obj1];
    NSDate *date2 = [dateFormatter dateFromString:obj2];
    return [date1 compare:date2];
}];

answered Jun 4, 2013 at 11:37

Anupdas

10.2k2 gold badges37 silver badges60 bronze badges

6 Comments

trojanfoe Over a year ago

Lots of conversion going on there, which cannot be efficient. What's wrong with converting the strings to dates before this? It will no doubt be useful whenever the array has to be presented or further processed.

Anupdas Over a year ago

@trojanfoe I just suggested a solution specific to the requirement. If I can I would never store dateString as such, but as NSDate instances. Thanks for your suggestion.

Sam B Over a year ago

this is the right answer

Anupdas Over a year ago

@SamBudda Thanks for ur good words. But the other answer was accepted as it has another way of doing the same thing much more efficiently. If date is stored as string, conversion is needed where ever it is used. Mine is more specific to sorting current array of dateStrings :)

Sam B Over a year ago

Problem with marked answer is that it is assuming the array has nsdate objects when clearly OP is storing strings. Just because the string looks like date doesn't mean iOS know they are dates. I have done this sort in the past and your way is correct as per OPs question

|

Antonio MG · Accepted Answer · 2013-06-04 11:38:19Z

1

You need to add them as NSDate objects, for that use this:

NSString *dateString = @"01/02/2010";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSDate *dateFromString = [[NSDate alloc] init];
dateFromString = [dateFormatter dateFromString:dateString];
[dateFormatter release];

Once the array contains NSDates, it will be sorted correctly

Or if you dont want to store NSDates, when you are comparing it, convert them to dates and compare them

answered Jun 4, 2013 at 11:38

Antonio MG

20.4k3 gold badges45 silver badges62 bronze badges

Comments

Mudit Bajpai · Accepted Answer · 2013-06-04 11:41:25Z

1

Store the dates as NSDate objects in an NS(Mutable)Array, then use [NSArray sortedArrayUsingSelector: or [NSMutableArray sortUsingSelector: and pass @selector(compare:) as the parameter. The -[NSDate compare:] method will order dates in ascending order for you.

answered Jun 4, 2013 at 11:41

Mudit Bajpai

3,01821 silver badges35 bronze badges

Collectives™ on Stack Overflow

How to sort Array of dates? [duplicate]

4 Answers 4

7 Comments

6 Comments

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

7 Comments

6 Comments

Comments

Comments

Linked

Related