[R] time zone - any practical solution?

Gabor Grothendieck ggrothendieck at gmail.com
Tue Jul 12 16:41:49 CEST 2011

On Tue, Jul 12, 2011 at 8:57 AM, B Laura <gm.spam2011 at gmail.com> wrote:
> Dear Gabor
> http://rwiki.sciviews.org/doku.php?id=tips:data-io:ms_windows&s=excel
> doesnt describe handling dates with daylight saving time issues.

Two references were given and its discussed in the R News article.  It
was also mentioned over again in my first post -- namely, don't use
POSIXct and then you don't have time zones and so all these problems
go away.

> R classes Date can remove time and timezone, however calculating days

You don't have to remove the time zone if you never use POSIXct.  Date
class has no time zones in the first place.

> difference between two manipulated variables same problem appear if handling
> these without Dates.

> R News 4/1 doesnt provide solution to this neither.

It certainly discusses how to choose the appropriate date / time
class.  Your problem is that you are using the wrong class for the
problem whereas you seem to be interpreting it as how to fix it up
after having chosen the wrong class.  By that time the wrong design
decision has already been made and that is what is fundamentally
causing the problem. The entire first page of  the  Rnews article
discusses choosing the right class in the first place.

Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

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