Sent from my phone. Please excuse my brevity.
On January 26, 2017 11:22:47 AM PST, William Dunlap via R-help <r-help at r-project.org> wrote:
>The R bug I mentioned was not that
> as.POSIXlt("2016-03-27 02:30", format="%Y-%m-%d %H:%M", tz="CET")
>returned an NA. That seems reasonable since there was no such time.
>
>The bug is that the POSIXlt object prints in an odd format (leaving
>off the time zone/daylight/standard time string) instead of printing
>an NA. This made it hard for you to see the problem.
>
>Using tz="GMT" or "UTC" will give 'solar' time England.
>tz="Etc/GMT-1" will give 'solar' time in central Europe.
>
>Bill Dunlap
>TIBCO Software
>wdunlap tibco.com
>
>
>On Thu, Jan 26, 2017 at 10:46 AM, rob vech <rob.vech87 at gmail.com>
>wrote:
>> Hi William,
>> asking to the r-devel list I resolved the problem! It depends from
>the
>> timezone (tz param) that I didn't specified and so R automatically
>uses my
>> local time and considers also the daylight saving time (that comes at
>2:00
>> at my position).
>> As my dates are in solar time, I specified the time zone as "GMT" and
>it
>> works!
>> Here a simple example:
>>
>> df = data.frame(DateTime = c(
>> '2016-12-21 10:34:54',
>> '2016-12-21 11:04:54',
>> '2016-12-21 11:34:54',
>> '2016-03-27 02:05:50',
>> '2016-03-27 02:35:50',
>> '2016-12-21 12:04:54',
>> '2016-12-21 12:34:54'
>> ))
>>
>>
>> df$DateTime = as.POSIXlt(strptime(df$DateTime,
>> format='%Y-%m-%d %H:%M:%S',
>> tz='GMT'))
>>
>> ord = order(as.numeric(strptime(df$DateTime, format='%Y-%m-%d
>%H:%M:%S',
>> tz='GMT')))
>>
>> df.ord = df[ord,1]
>> df.ord
>>
>
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