R devel - Feb 2011 - terribly annoying bug with POSIXlt : one o'clock is midnight?

Apparently, as.POSIXlt takes one o'clock as the start of the day :
> as.POSIXlt(0,origin="1970-01-01")
[1] "1970-01-01 01:00:00 CET"
> as.POSIXlt(0,origin="1970-01-01 00:00:00")
[1] "1970-01-01 01:00:00 CET"
> as.POSIXlt(0,origin="1970-01-01 23:59:59")
[1] "1970-01-02 00:59:59 CET"

Cheers



-- 
Joris Meys
Statistical consultant

Ghent University
Faculty of Bioscience Engineering
Department of Applied mathematics, biometrics and process control

tel : +32 9 264 59 87
Joris.Meys at Ugent.be
-------------------------------
Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php

Been too fast : I am in Central European Time (GMT +1), which explains
the time conversion. Still, I find it highly annoying that as.POSIXlt
assumes that the time is given in GMT and has to be converted to
whatever timezone you're in if you don't specify anything.

Probably this behaviour is not going to be changed, but it's causing
very hard-to-track-down bugs nonetheless.

Cheers
Joris

On Fri, Feb 4, 2011 at 4:21 PM, Joris Meys <jorismeys at gmail.com>
wrote:
> Apparently, as.POSIXlt takes one o'clock as the start of the day :
>
>> as.POSIXlt(0,origin="1970-01-01")
> [1] "1970-01-01 01:00:00 CET"
>> as.POSIXlt(0,origin="1970-01-01 00:00:00")
> [1] "1970-01-01 01:00:00 CET"
>> as.POSIXlt(0,origin="1970-01-01 23:59:59")
> [1] "1970-01-02 00:59:59 CET"
>
> Cheers
>
>
>
> --
> Joris Meys
> Statistical consultant
>
> Ghent University
> Faculty of Bioscience Engineering
> Department of Applied mathematics, biometrics and process control
>
> tel : +32 9 264 59 87
> Joris.Meys at Ugent.be
> -------------------------------
> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
>


-- 
Joris Meys
Statistical consultant

Ghent University
Faculty of Bioscience Engineering
Department of Applied mathematics, biometrics and process control

tel : +32 9 264 59 87
Joris.Meys at Ugent.be
-------------------------------
Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php

On Fri, 2011-02-04 at 16:21 +0100, Joris Meys wrote:
> Apparently, as.POSIXlt takes one o'clock as the start of the day :
> 
> > as.POSIXlt(0,origin="1970-01-01")
> [1] "1970-01-01 01:00:00 CET"
> > as.POSIXlt(0,origin="1970-01-01 00:00:00")
> [1] "1970-01-01 01:00:00 CET"
> > as.POSIXlt(0,origin="1970-01-01 23:59:59")
> [1] "1970-01-02 00:59:59 CET"
> 
> Cheers
Isn't this just a timezone thing? CET is an hour ahead of UTC (GMT)
> as.POSIXlt(0,origin="1970-01-01")
[1] "1970-01-01 01:00:00 BST"
> as.POSIXlt(0,origin="1970-01-01", tz = "GMT")
[1] "1970-01-01 GMT"
> as.POSIXlt(0,origin="1970-01-01 00:00:00")
[1] "1970-01-01 01:00:00 BST"
> as.POSIXlt(0,origin="1970-01-01 00:00:00", tz = "GMT")
[1] "1970-01-01 GMT"
> as.POSIXlt(0,origin="1970-01-01 23:59:59", tz = "GMT")
[1] "1970-01-01 23:59:59 GMT"

G
-- 
%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%
 Dr. Gavin Simpson             [t] +44 (0)20 7679 0522
 ECRC, UCL Geography,          [f] +44 (0)20 7679 0565
 Pearson Building,             [e] gavin.simpsonATNOSPAMucl.ac.uk
 Gower Street, London          [w] http://www.ucl.ac.uk/~ucfagls/
 UK. WC1E 6BT.                 [w] http://www.freshwaters.org.uk
%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%