Conversion of dates to a different format

6 views (last 30 days)
I need to convert 20110530 (2011 May 30) to 2011150 (which is the 150th day since January 01, 2011). How can i perform this task in MATLAB?

Accepted Answer

Star Strider
Star Strider on 6 Oct 2015
Edited: Star Strider on 6 Oct 2015
The new date and time functions probably have built-in functions to do what you want, but in their absence, this works:
t_str = '20110530';
dn = datenum('20110530', 'yyyymmdd');
dnstart = datenum(dt_str(1:4), 'yyyy'); % Start Of 2011
dayofyear = dn-dnstart+1
Result = sprintf('%4s%03d', dt_str(1:4),dayofyear)
Result =
The +1 is necessary for ‘dayofyear’ because it computes the difference between 01-Jan-2011 and doesn’t include 01-Jan-2011.
EDIT — Added ‘Result’ assignment.

Sign in to comment.

More Answers (2)

Peter Perkins
Peter Perkins on 7 Oct 2015
In R2014b or later, use datetime.
Convert a yyyyMMdd string to a datetime:
>> d = datetime('20110530','Format','yyyyMMdd')
d =
Change its display format to show day of year:
>> d.Format = 'yyyyDDD' % includes a leading zero for dates before 10 Apr
d =
Get the day of year as a number:
>> day(d,'dayofyear')
ans =
Convert to string (though you likely don't need to do this unless you're exporting to outside of MATLAB):
>> char(d) % or use cellstr for multiple dates
ans =
Convert a number in yyyyMMdd format to a datetime:
>> d = datetime(20110530,'ConvertFrom','yyyyMMdd')
d =
30-May-2011 00:00:00

Stephen23 on 6 Oct 2015
This is very easy using my FEX submissions datenum8601 and datestr8601:
>> X = datenum8601('20110530');
>> datestr8601(X,'yn')
ans =


Find more on Dates and Time in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!