On Thu, Jul 28, 2011 at 9:37 AM, Maciej Hoffman-Wecker <maciej.hoffman-wec...@bioskin.de> wrote: > Dear help list, > > I have a timestamp in as a chron object: > >> (x <- chron(dates = c("12/02/11", "22/11/11"), > + times = c("07:30:00", "04:00:00"), > + format = c(dates = "d/m/y", times = "h:m:s"))) > [1] (12/02/11 07:30:00) (22/11/11 04:00:00) > > Now I want to shift the timestamp by 06:30 (hh:mm) backwards, to get > > [1] (12/02/11 01:30:00) (21/11/11 21:30:00) >
Try this: x - as.numeric(times("06:30:00")) If you actually wanted 6 hours behind, which is what the desired result shown in the post implies, then use "06:00:00" instead. -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ R-help@r-project.org mailing list 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.