Here's an idea: > as.POSIXct(paste0("1963","-1-1"))+as.difftime(335,units="days") + > as.difftime(3, units="hours") [1] "1963-12-02 03:00:00 CET"
However, 2 caveats (a) I think you need to subtract 1 from the DOY (1 should be Jan 1, right?) (b) Beware Daylight Savings time: > as.POSIXct(paste0("2019","-1-1"))+as.difftime(160,units="days") + > as.difftime(3, units="hours") [1] "2019-06-10 04:00:00 CEST" This can be worked around as follows: > tt <- as.POSIXct(paste0("2019","-1-1"))+as.difftime(160,units="days") > ttl <- as.POSIXlt(tt) > ttl$hour=0 > ttl + as.difftime(3, units="hours") [1] "2019-06-10 03:00:00 CEST" ISOdate() and ISOdatetime() can also be used, again beware of time zones and DST. Also, ISOdate gives 12:00 GMT, whereas the POSIX stuff gives 0:00. -pd > On 23 Jan 2020, at 10:24 , Ogbos Okike <giftedlife2...@gmail.com> wrote: > > Dear Experts, > I have a data spanning 56 years from 1963 to 2018. > The datetime format is in DOY hour: > 1963 335 0 > 1963 335 1 > 1963 335 2 > 1963 335 3 > 1963 335 4 > 1963 335 5 > 1963 335 6 > 1963 335 7 > 1963 335 8 > 1963 335 9 > 1996 202 20 > 1996 202 21 > 1996 202 22 > 1996 202 23 > 1996 203 0 > 1996 203 1 > 1996 203 2 > 1996 203 3 > 2018 365 20 > 2018 365 21 > 2018 365 22 > 2018 365 23 > When I used: > as.Date(335,origin="1963-01-01"), for the first row, I got: > [1] "1963-12-02" > This is the format I want, though it is not yet complete. Time is missing. > > Again, I can't be doing this one after the other. I guess you have a > better way of handling this. I have spent some time trying to get it > right but I am really stuck. I would be most glad if you could spare > your busy time to help me again. > > Thank you very much for your usual kind assistance. > > Best regards > Ogbos > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.