Re: [R] POSIXlt and daylight savings time
pdb wrote:
>> as.POSIXlt('2004-10-31 02:00:00')
> [1] "2004-10-31"
>> as.POSIXlt('2004-10-31 03:00:00')
> [1] "2004-10-31 03:00:00"
>
> How do I tell as.POSIXlt() to ignore daylight savings and just convert to
> a time as is? I've read about the 'isdst' but it is still unclear what to
> do.
There *was* no 02:00:00 in your local timezone, so you’re trying to specifiy
a point in time that just didn’t exist. If you really want to do this, use
the UTC timezone, by setting the ‘tz’ argument in as.POSIXct/as.POSIXlt to
UTC (or GMT).
--
Karl Ove Hufthammer
E-mail: k...@huftis.org
Jabber: huf...@jabber.no
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Re: [R] POSIXlt and daylight savings time
Hello,
Jeff already answered to your question,
as.POSIXlt('2004-10-31 02:00:00', format = "%Y-%m-%d %H:%M:%S")
And in my system and timezone (GMT) I get
as.POSIXlt('2004-10-31 02:00:00')
[1] "2004-10-31 02:00:00"
So Jeff's point (b) should also be followed.
sessionInfo()
R version 2.15.1 (2012-06-22)
Platform: i386-pc-mingw32/i386 (32-bit)
locale:
[1] LC_COLLATE=Portuguese_Portugal.1252 LC_CTYPE=Portuguese_Portugal.1252
[3] LC_MONETARY=Portuguese_Portugal.1252 LC_NUMERIC=C
[5] LC_TIME=Portuguese_Portugal.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] fortunes_1.4-2 tools_2.15.1
Hope this helps,
Rui Barradas
Em 05-09-2012 09:24, pdb escreveu:
I'll rephrase the question...
If you try...
as.POSIXlt('2004-10-31 02:00:00')
you get
[1] "2004-10-31"
What do I need to do to make it return
[1] "2004-10-31 02:00:00"
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Re: [R] POSIXlt and daylight savings time
I'll rephrase the question...
If you try...
as.POSIXlt('2004-10-31 02:00:00')
you get
[1] "2004-10-31"
What do I need to do to make it return
[1] "2004-10-31 02:00:00"
--
View this message in context:
http://r.789695.n4.nabble.com/POSIXlt-and-daylight-savings-time-tp4642253p4642272.html
Sent from the R help mailing list archive at Nabble.com.
__
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Re: [R] POSIXlt and daylight savings time
a) Don't use POSIXlt in data frames... use POSIXct. POSIXlt is like a data
frame of its own, and data frames within data frames lead to surprising
results, to say the least.
b) I have had best luck using Sys.setenv( TZ="Etc/GMT+8" ) for US Pacific
Standard Time as "local" time for the duration of analysis.
c) Use the format argument if you want consistent results.
---
Jeff NewmillerThe . . Go Live...
DCN:Basics: ##.#. ##.#. Live Go...
Live: OO#.. Dead: OO#.. Playing
Research Engineer (Solar/BatteriesO.O#. #.O#. with
/Software/Embedded Controllers) .OO#. .OO#. rocks...1k
---
Sent from my phone. Please excuse my brevity.
pdb wrote:
>I have a data frame that contains dates, but when I use as.POSIXlt() I
>lose
>the hours on all records. I traced this down to a particuar hour which
>causes the issue...
>
>> as.POSIXlt('2004-10-31 02:00:00')
>[1] "2004-10-31"
>> as.POSIXlt('2004-10-31 03:00:00')
>[1] "2004-10-31 03:00:00"
>
>How do I tell as.POSIXlt() to ignore daylight savings and just convert
>to a
>time as is? I've read about the 'isdst' but it is still unclear what to
>do.
>
>This is a cleaned up date field that I received so adjusting the date
>itself
>is not possible.
>
>Thanks in advance.
>
>
>
>--
>View this message in context:
>http://r.789695.n4.nabble.com/POSIXlt-and-daylight-savings-time-tp4642253.html
>Sent from the R help mailing list archive at Nabble.com.
>
>__
>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] POSIXlt and daylight savings time
I have a data frame that contains dates, but when I use as.POSIXlt() I lose
the hours on all records. I traced this down to a particuar hour which
causes the issue...
> as.POSIXlt('2004-10-31 02:00:00')
[1] "2004-10-31"
> as.POSIXlt('2004-10-31 03:00:00')
[1] "2004-10-31 03:00:00"
How do I tell as.POSIXlt() to ignore daylight savings and just convert to a
time as is? I've read about the 'isdst' but it is still unclear what to do.
This is a cleaned up date field that I received so adjusting the date itself
is not possible.
Thanks in advance.
--
View this message in context:
http://r.789695.n4.nabble.com/POSIXlt-and-daylight-savings-time-tp4642253.html
Sent from the R help mailing list archive at Nabble.com.
__
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.
