在指定时区导入日期时间,而不考虑夏令时 [英] Import date-time at a specified timezone, disregard Daylight Savings Time
问题描述
我有一个从数据记录器获取的时间序列数据,该数据记录器设置为一个没有夏令时的时区( NZST 或UTC + 12:00),则数据跨度为数年。数据记录器不考虑DST更改,而是在有/没有DST的情况下与本地时间同步(取决于部署它的人)。
但是,当我将数据输入R ,我无法正确使用 as.POSIXct
忽略DST。我在具有以下设置的Windows计算机上使用的是R 2.14.0:
> Sys.timezone()
[1] NZDT
> Sys.getlocale( LC_TIME)
[1] English_New Zealand.1252
这是整个春季DST更改的三个时间戳,每个时间戳间隔1小时:
ts_str<-c( 28/09/2008 01:00, 28/09/2008 02:00, 28/09/2008 03:00)
> as.POSIXct(ts_str,format =%d /%m /%Y%H:%M,tz =)
[1] 2008-09-28 01:00:00 NZST NA
[3] 2008-09-28 03:00:00 NZDT
> as.POSIXct(ts_str,format =%d /%m /%Y%H:%M,tz = UTC)
[1] 2008-09-28 01:00:00 UTC 2008-09-28 02:00:00 UTC
[3] 2008-09-28 03:00:00 UTC
如您所见,时钟从1:59跳到3:00,所以2:00无效,因此不适用。此外,我可以使用 tz = UTC
使其忽略DST更改。但是,我宁愿保留正确的时区,因为我想将其他数据序列与 DST(NZDT或UTC + 13:00)一起记录下来(通过合并
)进行分析。
如何配置 tz
参数在MS Windows计算机上?我尝试了很多事情,例如 NZST,新西兰标准时间, UTC + 12:00, + 1200等,但是没有运气。还是修改其他设置?
您可以使用 tz = Etc / GMT + 12
:
as.POSIXct(ts_str,format =%d /%m /%Y %H:%M,tz = Etc / GMT + 12)
[1] 2008-09-28 01:00:00 GMT + 12 2008-09-28 02:00:00 GMT + 12
[3] 2008-09-28 03:00:00 GMT + 12
有关可用时区使用的完整列表,
dir(file.path(R.home( share ), zoneinfo),recursive = TRUE)
有几个.tab文件在那里不是时区,但包含一些信息,但是我的正则表达式不足以使用 dir
的pattern参数将它们排除。 p>
I have time series data obtained from a data logger that was set to one time zone without daylight savings (NZST or UTC+12:00), and the data spans a few years. Data loggers don't consider DST changes, and are synchronized to local time with/without DST (depending who deployed it).
However, when I get the data into R, I'm unable to properly use as.POSIXct
to ignore DST. I'm using R 2.14.0 on a Windows computer with these settings:
> Sys.timezone()
[1] "NZDT"
> Sys.getlocale("LC_TIME")
[1] "English_New Zealand.1252"
Here are three timestamps across the spring DST change, each are spaced 1 hour apart:
> ts_str <- c("28/09/2008 01:00", "28/09/2008 02:00", "28/09/2008 03:00")
> as.POSIXct(ts_str, format="%d/%m/%Y %H:%M", tz="")
[1] "2008-09-28 01:00:00 NZST" NA
[3] "2008-09-28 03:00:00 NZDT"
> as.POSIXct(ts_str, format="%d/%m/%Y %H:%M", tz="UTC")
[1] "2008-09-28 01:00:00 UTC" "2008-09-28 02:00:00 UTC"
[3] "2008-09-28 03:00:00 UTC"
As you can see, the clocks jumped forward at 1:59 to 3:00, so 2:00 is invalid, thus NA. Furthermore, I can use tz="UTC"
to get it to ignore DST changes. However, I'd rather keep the correct time zone since I have other data series recorded with DST (NZDT or UTC+13:00) that I'd like to blend in (via merge
) for my analysis.
How do I configure the tz
parameter on a MS Windows computer? I've tried many things, such as "NZST", "New Zealand Standard Time", "UTC+12:00", "+1200", etc., but no luck. Or do I modify some other setting?
You can use tz="Etc/GMT+12"
:
as.POSIXct(ts_str, format="%d/%m/%Y %H:%M", tz="Etc/GMT+12")
[1] "2008-09-28 01:00:00 GMT+12" "2008-09-28 02:00:00 GMT+12"
[3] "2008-09-28 03:00:00 GMT+12"
For a full list of available timezones use,
dir(file.path(R.home("share"),"zoneinfo"), recursive=TRUE)
There are a couple of of .tab files in there which aren't timezones but hold some information, but my regex-fu isn't good enough to be able to exclude them with the pattern argument to dir
.
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