On Fri, 12 Nov 2004 16:27:41 +0000, Bernie McConnell <[EMAIL PROTECTED]> wrote :
>Many thanks for the responses about how to read datetimes into POSIXct >which refer to straight GMT times without regard to Daylight Saving. To >reiterate, I''m using R 2.0.0 on win2000. > >I have tried Gabor's suggestion,see below, which did not work for me. The >fundamental setting (for me) appears to be in the registry: > >HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation > >The values here are most readily altered using the 'Date/ TIme properties' >window (just double click the wee digital clock on the right of the window >task bar). When I disable Daylight Saving a registry variable >called DisableAutoDaylightTimeSet is created and is set to 1. This can be >observed with regedit. Now all works perfectly with my date handling. So >it seems that setting the timezone to GMT is necessary but not sufficient >for my needs > >I confess that I do not understand the relationship between setting >registry variables and environment (eg TZ="GMT"). > >In practice I would like to keep my win200 machine with Daylight Saving >enabled - for the sake of other applications. One strategy is to make the >required registry alterations immediately before and after any R code which >handles dates. But then I'm rather worried whether continuously enabling / >disabling Daylight Saving would have dire consequences for other >applications and the well-being of my already shaky OS. Is this the right >route - and if so could someone please guide me how to achieve this in R >for win2000? > >Perhaps a better strategy would be to introduce some set-able option within >R that forced date handling to ignore Daylight Saving. But here I have >insufficient expertise and can only appeal to the continuing generosity of >the developer community. > >I am sure that there are many R users in the same position as me - but >perhaps they don't all realize it! I think you probably want to use as.is=TRUE when you retrieve the results, then use the date conversion functions to specify the time zone explicitly, e.g. asPOSIXct(x, tz='GMT'). Duncan Murdoch ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
