Hi [EMAIL PROTECTED] napsal dne 11.04.2008 12:47:57:
> Brian, > > > Thanks for your reply. The data I have was downloaded from a > government database so it now seems that the problem is how to > convert all the records in the format '1-Apr-08' to the format 2008-04-11. There is no need to convert it externally. Your Order.Made.Date is not time but factors. You need to to transform them to time/date format e.g. by time.data<-strptime(your data, format = .....) see as.Date for details. Then you can use them in your construction without any problem. Regards Petr > > I can ask the person working on the new version of this database > whether they will use this standard, it certainly isn't in common use. > > Your explanation did make the help files, which I typically struggle > with, clearer. > > > Bob > > > At 07:03 PM 11/04/2008, you wrote: > >You need to give the format -- might mean 2008-04-01 or 2001-04-08, > >and R refuses to guess. > > > >Please *do* read the help file (e.g. as.Date) before posting: the > >international standard format is , and Australia has adopted that standard. > > > >On Fri, 11 Apr 2008, Bob Green wrote: > > > >>Hello, > >> > >>I was hoping for advice regarding resolving the above error. > > > >Telling R what you intend is the usual way to resolve user errors > >caused by ambiguous input. > > > >> > >>I have a csv file that contains the following variable: > >> > >> $ Order.Made.Date : Factor w/ 299 levels > >>"1-Apr-08","1-Aug-05",..: 278 285 91 286 159 132 108 261 282 147 ... > >> > >> > >>I want to calculate a variable named F.length, which is today's date > >>minus the values contained in the variable: April$Order.Made.Date) > >>I tried altering the date format but continued to receive the same error. > >> > >> > F.length <- difftime ("11/04/2008", April$Order.Made.Date) > >> > Error in fromchar(as.character(x)) : character string is not in > >>a standard unambiguous format > >> > >> > Order.date <- as.Date (April$Order.Made.Date) > >> > Error in fromchar(x) : character string is not in a standard > >>unambiguous format > >> > Order.date <- 'as.POSIXlt' (April$Order.Made.Date) > >>Error in fromchar(as.character(x)) : character string is not in a > >>standard unambiguous format > >> > >>Any suggestions are appreciated, > >> > >>Bob > > > > > >-- > >Brian D. Ripley, [EMAIL PROTECTED] > >Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ > >University of Oxford, Tel: +44 1865 272861 (self) > >1 South Parks Road, +44 1865 272866 (PA) > >Oxford OX1 3TG, UK Fax: +44 1865 272595 > > ______________________________________________ > 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. ______________________________________________ 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.