Seems to work fine for me: > times <- c("10:12:34", "14:23:15") > Ptime <- as.POSIXct(strptime(times, "%H:%M:%S")) > > Ptime [1] "2008-10-05 10:12:34 GMT" "2008-10-05 14:23:15 GMT"
> difftime(Ptime[2], Ptime[1], units='min') Time difference of 250.6833 mins > You just have to be careful that all your times are for the same day since you do not have a 'date' associated with the time. On Sun, Oct 5, 2008 at 1:25 AM, Gouri Shankar Mishra <[EMAIL PROTECTED]> wrote: > Hi > > I have two columns of data with time in form of HH:MM:SS - representing > start time and end time of an activity. I am trying to calculate the time > difference (duration of the activity). > > (1) I first tried >> difftime(btime, etime, units = "mins") > This however gave me the error - Error in > as.POSIXlt.character(as.character(x)) : character string is not in a > standard unambiguous format > > (2) The above error message indicated some problem in format. So I tried >> etime1=as.date(etime, %H:%M:%S") > This gave me the Error: unexpected SPECIAL in "etime1=as.date(etime, %H:%" > > I also tried >>etime1=format(etime, %H:%M:%S") > But this gave a similar error - unexpected SPECIAL in "etime1=format(etime, > %H:%" > > Any suggestions? > > Regards > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.