iOS How to get day number of the year?

Question

Possible Duplicate:
How do you calculate the day of the year for a specific date in Objective C

I need to get the day number of the year and don't know which would be the best aproach.

Example:

21-jan-2012 -> 21

2-feb-2012 -> 33

2-mar-2012 -> 62

2-mar-2011 -> 61

Any ideas?

Thanks

Why the downvotes? This is a valid question to a valid logic need? — davidethell, Jun 14 '12 at 09:18

Rok Jarc · Answer 1 · 2015-05-04T06:28:25.300

22

I'm a little late for the party but anyway, here it goes:

 NSDate *today = [NSDate date];
 NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"DDD"];
 NSInteger dayInYear = [[dateFormat stringFromDate:today] integerValue];
 NSLog(@"today is %d. day in year", dayInYear);

result for 14.jun.2012: today is 166. day in year

EDIT: i was amazed that there was no easy-to-find example on Google.

You could also use format @"DD" to get day in month or @"D" to get day in week.

EDIT2: Just a note: creating NSDateFormatter can be quite expensive operation. If your class uses this function frequently you might want to create a static formatter ivar.

edited May 04 '15 at 06:28

answered Jun 14 '12 at 09:41

Rok Jarc

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+1 for using NSDateFormatter to solve the problem. I love having two ways to do something. – davidethell Jun 14 '12 at 09:44
Thanks! +1 back at you :) I agree, more ways to do something is certainly fun. – Rok Jarc Jun 14 '12 at 09:47

score -1 · Accepted Answer · answered Jun 14 '12 at 09:17

-1

Look at NSTimeInterval. You can get the seconds elapsed between two dates:

NSTimeInterval secondsElapsed = [secondDate timeIntervalSinceDate:firstDate];

So your firstDate can be the beginning of the year. Then you can just divide by 3600*24 (seconds per day) to get the days.

answered Jun 14 '12 at 09:17

davidethell

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This is actually not correct, I'm new to the topic but using NSCalendar (or NSDateFormatter) would be the safer approach: http://infiniteundo.com/post/25326999628/falsehoods-programmers-believe-about-time – Chris Conover Nov 20 '13 at 20:58
The [docs](https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/DatesAndTimes/Articles/dtCalendars.html#//apple_ref/doc/uid/TP40003470-SW7) also cover this: "If you instead want to know what number day of the year it is you can use the ordinalityOfUnit:inUnit:forDate: method of the NSCalendar class." – Chris Conover Nov 20 '13 at 21:07

score -1 · Answer 3 · answered Jun 14 '12 at 09:35

Check out the below solution You have to use timeIntervalSinceDate: for this

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init] ;
    [dateFormatter setDateFormat:@"yyyy-MM-dd"];

    NSDate *date1 = [dateFormatter dateFromString:@"2012-01-01"];
    NSDate *date2 = [NSDate date]; 
    NSLog(@"date %@ ", date2);

    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setDateFormat:@"yyyy-MM-dd"];

    NSDateFormatter *timeFormat = [[NSDateFormatter alloc] init];
    [timeFormat setDateFormat:@"HH:mm:ss"];

    NSDate *now = [[NSDate alloc] init];

    NSString *theDate = [dateFormat stringFromDate:now];
    NSDate *dt = [dateFormat dateFromString:theDate];


    NSTimeInterval diffDays = [dt timeIntervalSinceDate:date1];
    NSLog(@"Date %f ^^^^ ", diffDays/(24*60*60));

score -3 · Answer 4 · answered Jun 14 '12 at 09:17

-3

At first You create a Dictionnary like :

[Jan => 30,
Feb =>  28,
 ...]

With all days per month.

Secondly with your date like : 13 June 2012.
You'll add all value of the month before june (a while on your dictionnary).
And finish by add the day (here : 13).

answered Jun 14 '12 at 09:17

Damien Locque

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what about leap years? this is not a good practice – Jasper Jul 16 '13 at 07:32

iOS How to get day number of the year?

4 Answers4