[R] POSIX, time zone and Windows

[Gabor Grothendieck]

On 5/21/06, Patrick Giraudoux <patrick.giraudoux at univ-fcomte.fr> wrote:
> Excellent! Thanks a lot. Solution general enough, simple and
> understandable. Will try and stick on it...
>
> Should be nice to add this simple and clear example to the as.POSIXxx
> documentation.

Note that it is system dependent.  tz = "" and tz = "GMT" generally
work but other formats may or may not.

>
> Thanks again,
>
> Patrick
>
> jim holtman a écrit :
> > forgot, in your case it should be:
> >
> > tz="chs-8chd"
> >
> > > (x <- as.POSIXct(mydate, tz='chs-8chd'))
> > [1] "2006-05-16 11:30:00 chd"
> > > format(x, tz="GMT")
> > [1] "2006-05-16 02:30:00"
> > >
> >
> >
> >
> > On 5/21/06, *Patrick Giraudoux* <patrick.giraudoux at univ-fcomte.fr
> > <mailto:patrick.giraudoux at univ-fcomte.fr>> wrote:
> >
> >     Dear Listers,
> >
> >     Apologize to pile up on the 'tz' issue in POSIX objects. I have a
> >     'simple' thing on which I must make up my mind but cannot do it
> >     from the
> >     existing R-help threads. I am currently working on dog telemetry in
> >     China, and download time information from GPS collars. I would like to
> >     set up the corresponding POSIXxx variables in R to a given time
> >     zone. Eg
> >     Pekin GMT+8:00.
> >
> >     I cannot find out how to do it properly. For instance:
> >
> >     mydate<-""06/05/16/11:30:00""
> >     mydate<-strptime(mydate, "%y/%m/%d/%H:%M:%S")
> >
> >     mydate
> >     [1] "2006-05-16 11:30:00"
> >     as.POSIXct(mydate)
> >     [1] "2006-05-16 11:30:00 Paris, Madrid"
> >
> >     Which is obviously not what I wish regarding the specification Paris,
> >     Madrid...
> >
> >     I have tried to pass something to the argument tz
> >
> >     mydate2<-strptime(mydate, "%y/%m/%d/%H:%M:%S",tz="GMT") or
> >     mydate2<-strptime(mydate, "%y/%m/%d/%H:%M:%S",tz="GMT+08")
> >
> >     I get this:
> >
> >     mydate2
> >     [1] NA
> >
> >     Is there a way to specify the time zone on which I was working
> >     (actually
> >     GTM + 8:00)? I have read in R-help that this is system dependent, but
> >     the how to do it still escape. Working with Windows, I have
> >     checked the
> >     following address given by Gabor Grothendieck in R-help,
> >     http://msdn2.microsoft.com/en-us/library/90s5c885.aspx, but I cannot
> >     manage with the syntax: *TZ*=tzn[+ | –]hh[*:*mm[*:*ss] ][dzn]. They
> >     mention a three lettre time zone (where can the corresponding codes be
> >     found?) to which to add a difference in hours between UTC and the
> >     local
> >     time... but any trial I did specifying tz="UTM+08" or other
> >     combination
> >     leads nowhere...
> >
> >     Thanks for any hint...
> >
> >     Patrick
> >
> >     ______________________________________________
> >     R-help at stat.math.ethz.ch <mailto:R-help at 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
> >
> >
> >
> >
> > --
> > Jim Holtman
> > Cincinnati, OH
> > +1 513 646 9390 (Cell)
> > +1 513 247 0281 (Home)
> >
> > What is the problem you are trying to solve?
>
>        [[alternative HTML version deleted]]
>
>
>
> ______________________________________________
> R-help at 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
>
>