The first number is the year, the second is the month and the third is the day. It ignores trailing characters.
> library(chron) > f <- function(x) str(month.day.year(as.Date(x))) > f("2001/1/1") List of 3 $ month: num 1 $ day : num 1 $ year : num 2001 > f("1/1/2001") List of 3 $ month: num 1 $ day : num 20 $ year : num 1 > # trailing 01 ignored. > f("13/1/2001") List of 3 $ month: num 1 $ day : num 20 $ year : num 13 > # no 13th month > as.Date("1/13/2001") Error in fromchar(x) : character string is not in a standard unambiguous format On Thu, Jan 22, 2009 at 1:54 PM, Marie Sivertsen <mariesiv...@gmail.com> wrote: > Dear Brian, > > I dont understand what you mean. The thread was about the as.Date which you > suggested to be used instead of the as.date. Following your advice I tried > the as.Date and have questions about the observed behaviour, which was > surprising to me. Is this what you call hijacking? Do you mean I ought > start a new thread instead? I thought my question were relevant to the > threads' subject. I am sorry if it were not. > > So here is the questions once again: why do the as.Date behave as in my > examples below, is this intended? > > > > On Thu, Jan 22, 2009 at 3:55 PM, Brian D Ripley <rip...@stats.ox.ac.uk>wrote: > >> You've hijacked a thread here. >> >> >> On Thu, 22 Jan 2009, Marie Sivertsen wrote: >> >> >>> I am relatively new to R, so maybe I am miss something, but I now tried >>> the a >>> s.Date now and have problems understanding how it works (or don't work as >>> it seem). >>> >>> Brian D Ripley wrote: >>> > On Thu, 22 Jan 2009, Terry Therneau wrote: >>> >> >>> >> One idea is to use the as.date function, for the older (and less >>> capable) 'date' >>> >> class. This is currently loaded by default with library(survival). It >>> re >>> turns >>> >>> >> NA for an invalid date rather than dying. >>> > >>> > So does as.Date *if you specify the format* (as you have to with your >>> as.da >>> te: >>> > it has a default one): >> >> > > My examples: > > > >> >>> as.Date("2001/1/1") >>> Works fine >>> as.Date("1/1/2001") >>> Prints "1-01-20" ??? >>> as.Date("13/1/2001") >>> Prints "13-01-20" ??? >>> >>> as.Date("1/13/2001") >>> Prints error: not in standard unambigous format >>> It seems that as if both "1/1/2001" and "13/1/2001" were considered by R >>> to b >>> e in a standard unambiguous format (or otherwise an error be reported?) >>> and yet they >>> >>> >>> are parsed incorrectly according to what one could think is obvious. It >>> is a >>> lso surprizing that not only "13/1/2001" but also "1/2/2001" and >>> "2/1/2001" are successful but incorrect parsed as if they are unambiguous, >>> and yet >>> "13/1/2001" is ambiguous, though there is really just one way to parse it >>> meaningfully. >>> I think the strings that are incorrectly parsed should raise errors, and >>> the last example should be succesful parsed. What is the reason for the >>> observed >>> ? >>> >>> >>> > > > Mvh. > Marie > > > >> >>> >> -- >> Brian D. Ripley, rip...@stats.ox.ac.uk >> Professor of Applied Statistics, >> http://www.stats.ox.ac.uk/~ripley/<http://www.stats.ox.ac.uk/%7Eripley/> >> University of Oxford, Tel: +44 1865 272861 (self) >> 1 South Parks Road, +44 1865 272866 (PA) >> Oxford OX1 3TG, UK Fax: +44 1865 272595 >> > > [[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. > ______________________________________________ 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.