Message-ID: <f3dcf28e-83ab-4350-a98a-e51a3f43fe59@email.android.com>
Date: 2012-12-06T14:54:38Z
From: Jeff Newmiller
Subject: Incorrect DST time changes in DateTimeClasses
In-Reply-To: <2A4CFB23-88F8-4315-AFD2-2B579828A215@mac.com>
What OS are you using? It makes a difference.
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Andrew Digby <andrewdigby at 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]]
>
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