Thanks for confirming that it's a wider problem. I thought that /etc/localtime on my machine was the Olsen database, but presumably not, since the DST changes are correct in that file. Unless R is reading that file incorrectly?
I've ended up using chron (which ignores time zones and DST) and a custom DST file as a workaround. Thanks again. On 7/12/2012, at 11:20 , Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > I see this discontinuity at '2010-04-04 02:26:05' on my Windows 7 x64 with R > 2.15.2. I also see it for time zone "America_Los_Angeles" at '2010-11-07 > 01:23:09'. > > I am not entirely sure what the "correct" behavior should be, since the > string does not specify whether it is in daylight or standard time, even > though it could be either for any time between 2:00 and 3:00 (or 1:00 and > 2:00 for "America/Los_Angeles"). > > In any event, if this is an issue it appears to be an Olsen timezone database > issue, not an R issue. > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > --------------------------------------------------------------------------- > Sent from my phone. Please excuse my brevity. > > Andrew Digby <andrewdi...@mac.com> wrote: > >> >> Apologies - I intended to add that info at the end: OS X 10.8.2 and R >> 2.15.1. >> >> Many thanks. >> >>> R.Version() >> $platform >> [1] "x86_64-apple-darwin9.8.0" >> $arch >> [1] "x86_64" >> $os >> [1] "darwin9.8.0" >> $system >> [1] "x86_64, darwin9.8.0" >> $status >> [1] "" >> $major >> [1] "2" >> $minor >> [1] "15.1" >> $year >> [1] "2012" >> $month >> [1] "06" >> $day >> [1] "22" >> $`svn rev` >> [1] "59600" >> $language >> [1] "R" >> $version.string >> [1] "R version 2.15.1 (2012-06-22)" >> $nickname >> [1] "Roasted Marshmallows" >> >> >> On 7/12/2012, at 04:29 , Uwe Ligges <lig...@statistik.tu-dortmund.de> >> wrote: >> >>> >>> >>> On 06.12.2012 15:54, Jeff Newmiller wrote: >>>> What OS are you using? It makes a difference. >>> >>> ... and R version. >>> >>> Uwe Ligges >>> >>>> >> --------------------------------------------------------------------------- >>>> Jeff Newmiller The ..... ..... Go >> Live... >>>> DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. >> Live Go... >>>> Live: OO#.. Dead: OO#.. >> Playing >>>> Research Engineer (Solar/Batteries O.O#. #.O#. >> with >>>> /Software/Embedded Controllers) .OO#. .OO#. >> rocks...1k >>>> >> --------------------------------------------------------------------------- >>>> Sent from my phone. Please excuse my brevity. >>>> >>>> Andrew Digby <andrewdi...@mac.com> wrote: >>>> >>>>> >>>>> Can anyone please shed any light on why R DateTimeClasses give >> weird >>>>> times for when daylight saving time information changes, and which >>>>> aren't consistent with the OS? >>>>> >>>>> Example: >>>>> >>>>> Expected result: in New Zealand DST stopped (NZDT -> NZST) at >> 03:00 >>>>> NZDT on 2010-04-04, as confirmed by the OS time zone info (OS X >>>>> 10.8.2): >>>>> >>>>> zdump -v /etc/localtime >>>>> /etc/localtime Sat Apr 3 13:59:59 2010 UTC = Sun Apr 4 >> 02:59:59 >>>>> 2010 NZDT isdst=1 >>>>> /etc/localtime Sat Apr 3 14:00:00 2010 UTC = Sun Apr 4 >> 02:00:00 >>>>> 2010 NZST isdst=0 >>>>> >>>>> Result in R: R has DST changing at 02:26:08, instead of 03:00! >>>>> >>>>> > a<-as.POSIXlt('2010-04-04 02:26:07',tz="NZ") >>>>> > a$isdst >>>>> [1] 1 >>>>> > b<-as.POSIXlt('2010-04-04 02:26:08',tz="NZ") >>>>> > b$isdst >>>>> [1] 0 >>>>> >>>>> >>>>> So does R get its DST information from somewhere else? Any >> suggestions >>>>> would be much appreciated! >>>>> >>>>> Thanks >>>>> >>>>> [[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. >>>> > ______________________________________________ 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.