Dear friends - I have further problems handling dates_times, as
demonstrated below where concatenating two formatted vectors of
date_times results in errors.
I wonder why this happens and what was wrong in trying to take these two
vectors together
All best wishes
Troels Ring
Aalborg, Denmark
Windows
R version 3.3.2 (2016-10-31)
A <- structure(c(1364450400, 1364450400, 1364536800, 1364623200,
1364709600,
1364796000, 1364882400, 1364968800, 1365055200, 1365141600, 1365228000,
1365314400, 1365400800), class = c("POSIXct", "POSIXt"),
tzone = "UTC")
A
B <- structure(c(1365141600, 1365228000, 1365314400, 1365400800,
1365487200,
1365573600, 1365660000, 1365746400, 1365832800, 1365919200, 1366005600,
1366092000), class = c("POSIXct", "POSIXt"), tzone =
"UTC")
B
C <- c(A,B)
C
Hi Troels, I get no error. I think we need more information to be of any help. Best wishes, Ulrik On Fri, 7 Apr 2017 at 08:17 Troels Ring <tring at gvdnet.dk> wrote:> Dear friends - I have further problems handling dates_times, as > demonstrated below where concatenating two formatted vectors of > date_times results in errors. > I wonder why this happens and what was wrong in trying to take these two > vectors together > All best wishes > Troels Ring > Aalborg, Denmark > Windows > R version 3.3.2 (2016-10-31) > > > A <- structure(c(1364450400, 1364450400, 1364536800, 1364623200, > 1364709600, > 1364796000, 1364882400, 1364968800, 1365055200, 1365141600, 1365228000, > 1365314400, 1365400800), class = c("POSIXct", "POSIXt"), tzone = "UTC") > A > B <- structure(c(1365141600, 1365228000, 1365314400, 1365400800, > 1365487200, > 1365573600, 1365660000, 1365746400, 1365832800, 1365919200, 1366005600, > 1366092000), class = c("POSIXct", "POSIXt"), tzone = "UTC") > B > C <- c(A,B) > C > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. >[[alternative HTML version deleted]]
Thanks a lot - perhaps it is just understanding how times dates are handled, sorry to bother if that is just the case C[1]==A[1] # TRUE but C[1] [1] "2013-03-28 07:00:00 CET" A[1] [1] "2013-03-28 06:00:00 UTC" Den 07-04-2017 kl. 08:27 skrev Ulrik Stervbo:> Hi Troels, > > I get no error. I think we need more information to be of any help. > > Best wishes, > Ulrik > > On Fri, 7 Apr 2017 at 08:17 Troels Ring <tring at gvdnet.dk> wrote: > >> Dear friends - I have further problems handling dates_times, as >> demonstrated below where concatenating two formatted vectors of >> date_times results in errors. >> I wonder why this happens and what was wrong in trying to take these two >> vectors together >> All best wishes >> Troels Ring >> Aalborg, Denmark >> Windows >> R version 3.3.2 (2016-10-31) >> >> >> A <- structure(c(1364450400, 1364450400, 1364536800, 1364623200, >> 1364709600, >> 1364796000, 1364882400, 1364968800, 1365055200, 1365141600, 1365228000, >> 1365314400, 1365400800), class = c("POSIXct", "POSIXt"), tzone = "UTC") >> A >> B <- structure(c(1365141600, 1365228000, 1365314400, 1365400800, >> 1365487200, >> 1365573600, 1365660000, 1365746400, 1365832800, 1365919200, 1366005600, >> 1366092000), class = c("POSIXct", "POSIXt"), tzone = "UTC") >> B >> C <- c(A,B) >> C >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. >> > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. >
Thanks a lot - good idea: I put Sys.setenv(TZ = "UTC") ahead of the code - solves the problem! Thanks a lot Den 07-04-2017 kl. 09:26 skrev Mark Leeds:> Hi Troels: This is off-list so as to not clog the list with my noise > because my suggestion may not work. I really don't know that much > about time-zones. but. I ran your code and it "worked" but all the > times were correctly time stamped but they changed from UTC to GMT. > in time-zone. In your > case, they changed to something and the time got shifted it looks > like. So, definitely it has to do with how your time-zones are set. In > my .Rprofile, I have something. > Let me check. ... time passes ..... I have below in my .Rprofile. So > my guess is that, if you want things to remain UTC, then put below > in your .Rprofile but change it from "GMT" to "UTC". Others may have > different solutions but that might work. If you don't have that, then > R decides what to use and I'm not sure how it decides. > > Sys.setenv(TZ = "GMT") > > #print("LOADING MASS LIBRARY") > #ibrary("MASS") > #print("LOADING LATTICE LIBRARY") > #library("lattice") > > > > > :~> > > On Fri, Apr 7, 2017 at 3:00 AM, Troels Ring <tring at gvdnet.dk > <mailto:tring at gvdnet.dk>> wrote: > > Thanks a lot - perhaps it is just understanding how times dates > are handled, sorry to bother if that is just the case > > C[1]==A[1] # TRUE > > but > > C[1] > [1] "2013-03-28 07:00:00 CET" > A[1] > [1] "2013-03-28 06:00:00 UTC" > > > > > > > Den 07-04-2017 kl. 08:27 skrev Ulrik Stervbo: > > Hi Troels, > > I get no error. I think we need more information to be of any > help. > > Best wishes, > Ulrik > > On Fri, 7 Apr 2017 at 08:17 Troels Ring <tring at gvdnet.dk > <mailto:tring at gvdnet.dk>> wrote: > > Dear friends - I have further problems handling > dates_times, as > demonstrated below where concatenating two formatted > vectors of > date_times results in errors. > I wonder why this happens and what was wrong in trying to > take these two > vectors together > All best wishes > Troels Ring > Aalborg, Denmark > Windows > R version 3.3.2 (2016-10-31) > > > A <- structure(c(1364450400, 1364450400, 1364536800, > 1364623200, > 1364709600, > 1364796000, 1364882400, 1364968800, 1365055200, > 1365141600, 1365228000, > 1365314400, 1365400800), class = c("POSIXct", "POSIXt"), > tzone = "UTC") > A > B <- structure(c(1365141600, 1365228000, 1365314400, > 1365400800, > 1365487200, > 1365573600, 1365660000, 1365746400, 1365832800, > 1365919200, 1366005600, > 1366092000), class = c("POSIXct", "POSIXt"), tzone = "UTC") > B > C <- c(A,B) > C > > ______________________________________________ > R-help at r-project.org <mailto:R-help at r-project.org> mailing > list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > <https://stat.ethz.ch/mailman/listinfo/r-help> > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > <http://www.R-project.org/posting-guide.html> > and provide commented, minimal, self-contained, > reproducible code. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org <mailto:R-help at r-project.org> mailing > list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > <https://stat.ethz.ch/mailman/listinfo/r-help> > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > <http://www.R-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > > > ______________________________________________ > R-help at r-project.org <mailto:R-help at r-project.org> mailing list -- > To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > <https://stat.ethz.ch/mailman/listinfo/r-help> > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > <http://www.R-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > >[[alternative HTML version deleted]]
R does a poor job of supporting timezone-specific objects... you have to transfer the necessary attributes explicitly for many operations. (It does no job of supporting element-specific timezones so don't go there.) The good news is that R is pretty good at working with points in time, since the default behavior of implementing time with numeric values in GMT always means you can specify whatever timezone you want input or output to use, and the timestamps are always ordered correctly in time. I find that using the default empty string for tz attributes on POSIXt objects (meaning use whatever is default) and letting the TZ environment variable control the "current default" timezone is the most effective way to avoid frustration with this. Don't hesitate to change that variable when you need to convert to or from character or POSIXlt.. Sys.setenv( TZ="Etc/GMT+5" ) # read ?Olson x <- as.POSIXct( "2017-03-31 19:00:00" ) Sys.setenv( TZ="Etc/GMT+8" ) y <- as.POSIXct( "2017-03-31 16:00:00" ) Sys.setenv( TZ="GMT" ) print( x ) print( y ) -- Sent from my phone. Please excuse my brevity. On April 7, 2017 12:00:52 AM PDT, Troels Ring <tring at gvdnet.dk> wrote:>Thanks a lot - perhaps it is just understanding how times dates are >handled, sorry to bother if that is just the case > >C[1]==A[1] # TRUE > >but > >C[1] >[1] "2013-03-28 07:00:00 CET" >A[1] >[1] "2013-03-28 06:00:00 UTC" > > > > > >Den 07-04-2017 kl. 08:27 skrev Ulrik Stervbo: >> Hi Troels, >> >> I get no error. I think we need more information to be of any help. >> >> Best wishes, >> Ulrik >> >> On Fri, 7 Apr 2017 at 08:17 Troels Ring <tring at gvdnet.dk> wrote: >> >>> Dear friends - I have further problems handling dates_times, as >>> demonstrated below where concatenating two formatted vectors of >>> date_times results in errors. >>> I wonder why this happens and what was wrong in trying to take these >two >>> vectors together >>> All best wishes >>> Troels Ring >>> Aalborg, Denmark >>> Windows >>> R version 3.3.2 (2016-10-31) >>> >>> >>> A <- structure(c(1364450400, 1364450400, 1364536800, 1364623200, >>> 1364709600, >>> 1364796000, 1364882400, 1364968800, 1365055200, 1365141600, >1365228000, >>> 1365314400, 1365400800), class = c("POSIXct", "POSIXt"), tzone >"UTC") >>> A >>> B <- structure(c(1365141600, 1365228000, 1365314400, 1365400800, >>> 1365487200, >>> 1365573600, 1365660000, 1365746400, 1365832800, 1365919200, >1366005600, >>> 1366092000), class = c("POSIXct", "POSIXt"), tzone = "UTC") >>> B >>> C <- c(A,B) >>> C >>> >>> ______________________________________________ >>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >>> 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. >>> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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 at r-project.org mailing list -- To UNSUBSCRIBE and more, see >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.