Background: OS: Linux Mandrake 10.1 release: R 2.1.1 editor: GNU Emacs 21.3.2 front-end: ESS 5.2.3 ---------------------------------
Thanks to Brian Ripley (I've upgraded from source, thanks for the reminder) and Petr Pikal for their suggestions, but I have not made clear the form of my data: Browse[1]> ceduna[1:10,] LSD AVIATION_ID WND_DIR WND_SPD_MPS 1 1/01/2001 10:30:00 YCDU 230 4.6 2 1/01/2001 11:00:00 YCDU 210 4.1 3 1/01/2001 11:30:00 YCDU 230 6.7 4 1/01/2001 12:00:00 YCDU 230 7.7 5 1/01/2001 12:30:00 YCDU 220 8.2 6 1/01/2001 13:00:00 YCDU 210 7.2 7 1/01/2001 13:30:00 YCDU 210 7.2 8 1/01/2001 14:00:00 YCDU 200 6.7 9 1/01/2001 14:30:00 YCDU 190 7.7 10 1/01/2001 15:00:00 YCDU 200 8.2 Browse[1]> class(ceduna) [1] "data.frame" Browse[1]> x <- as.character(ceduna$LSD) Browse[1]> new.time <- strptime(x, "%d/%m/%Y %H:%M:%S") Browse[1]> class(new.time) [1] "POSIXt" "POSIXlt" Browse[1]> unique(new.time) Error in unique.default(new.time) : unique() applies only to vectors Browse[1]> tt <- new.time[!duplicated(unclass(new.time))] Error in duplicated.default(unclass(new.time)) : duplicated() applies only to vectors Browse[1]> I'm obviously doing something silly with the data classes, but what? Best fishes Sam ---- Sam McClatchie, Biological oceanography South Australian Aquatic Sciences Centre PO Box 120, Henley Beach 5022 Adelaide, South Australia email <[EMAIL PROTECTED]> Cellular: 0431 304 497 Telephone: (61-8) 8207 5448 FAX: (61-8) 8207 5481 Research home page <http://www.members.iinet.net.au/~s.mcclatchie/> /\ ...>><xX(°> //// \\\\ <°)Xx><< ///// \\\\\\ ><(((°> >><(((°> ...>><xX(°>O<°)Xx><< ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html