similar to: timezone conversion difficulties with the new US daylight saving time switch over

tplate at acm.org wrote: > Running under Windows XP 64 bit, as.POSIXlt()/as.POSIXct() seem > to think that US time zones (EST5EDT, MST7MDT) switched from daylight > savings back to standard time on Oct 28, 2007, whereas the switch > is actually on Sun Nov 04, 2007. > > =20 Not Our Problem. (This sort of thing never is. We are wholly dependent=20 on the OS for this information).

Running under Windows XP 64 bit, as.POSIXlt()/as.POSIXct() seem to think that US time zones (EST5EDT, MST7MDT) switched from daylight savings back to standard time on Oct 28, 2007, whereas the switch is actually on Sun Nov 04, 2007. Examples: > Sys.timezone() [1] "Mountain Daylight Time" > as.POSIXct("2007-10-30 12:38:47") [1] "2007-10-30 12:38:47 Mountain

So let me try to raise this issue once more, and perhaps be more clear about what I think the issue is.. In my opinion there is now a bug in make check in R-development (tested today with r79361). As I see it, I specify a reasonable TZ environment variable and this leads to make check emitting an error. Best, Kasper On Fri, Oct 2, 2020 at 11:28 AM Kasper Daniel Hansen < kasperdanielhansen

Yes, you are absolutely right and I'm pretty sure this will be fixed in one way or another. IMO, the failing test should simply use all.equal.POSIXt's new argument check.tzone=FALSE. Two simple alternatives modifying all.equal.POSIXt behaviour: - make check.tzone=FALSE the default: this is inconsistent with other arguments of all.equal methods, always defaulting to stricter checks -

Tracking down this bug was joint work with Jermoe Asselin (jerome at hivnet.ubc.ca) and Patrick Connolly (p.connolly at hortresearch.co.nz). We collectively were able to determine that this is a problem in both Windows 2000 and in Linux and by testing it in our three time zones that it seems to be daylight savings time related. Conversion of POSIXlt datetimes to POSIXct appears to have problems.

Thank you for the report. In R-devel, all.equal.POSIXt() by default reports inconsistent time zones. Previously, > x <- Sys.time() > all.equal(x, as.POSIXlt(x, tz = "EST5EDT")) would return TRUE. To ignore the time zone attributes in R-devel, the argument 'check.tzone = FALSE' needs to be used. That said, I can reproduce the 'make check' failure in R-devel on

Yes, the potential issue I see is that make check fails when I explicitly set TZ. However, I set it to be the same as what the system reports when I login. Details: The system (RHEL) I am working on has $ strings /etc/localtime | tail -n 1 EST5EDT,M3.2.0,M11.1.0 $ date +%Z EDT $ echo $TZ US/Eastern On Fri, Oct 2, 2020 at 9:48 AM Sebastian Meyer <seb.meyer at fau.de> wrote: > Thank

I have found what looks like a small problem in trunc.POSIXt() involving the transition to/from standard time and daylight savings time. Assuming my assessment is correct, I have a potential solution to offer. If a time in daylight savings time is rounded such that the rounded value is on the other side of the transition, the isdst element does not get changed accordingly. I have tested only

The following code: cut(as.POSIXct("2009-11-01 04:00:00", tz="America/Los_Angeles"), "1 day") gives the error: Error in seq.int(0, to - from, by) : 'to' must be finite This is related to November 1st, 2009 being the switchover date from daylight savings time to standard time in the America/Los_Angeles time zone. In particular, in cut.POSIXt, the starting

I have asked this question before, and received some suggestions for work-arounds that get the job done--and they are much appreciated. But I would still like to find out if I'm missing something, and whether there is a direct way using POSIXt functions (as.POSIXct, as.POSIXlt, strptime, in particular). I have environmental data collected once per minute. Here is a subset of 3 input

Hello, Suppose we need a function that takes a POSIXct object and need to calculate the time difference between it and GMT time: gmtDiff <- function(time) { time.gmt <- as.POSIXct(format(time, tz="GMT")) time.plt <- as.POSIXlt(time) dlstime <- ifelse(time.plt$isdst > 0, 1, 0) timezone <- as.numeric(difftime(time, time.gmt, units="hours"))

The return value of Sys.time() today with a timezone of US/Eastern is unchanged between 4.0.3-patched and devel, but on devel the following test fails all.equal(x, as.POSIXlt(x)) with x = Sys.time() This means that devel does not complete make tests (failure on tests/reg-tests-2.R) It is entirely possible that it is an error on my end, I use export TZ="US/Eastern" but I have been

Apologies for the intrusion. I am a lurker on list. I have been working to convert a digitized signal from a matlab file into R for analysis and other applications. R.matlab is working fine, and it is easy to convert the matlab date-time number (days since year 0) into R date-time numbers (seconds since 1970-01-01). Unfortunately, when I cast the R date-time number into POSIXct format it seems

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

I have some questions and comments on timezones. Problem 1. # get current time in current time zone > (now <- Sys.time()) [1] "2003-07-29 18:23:58 Eastern Daylight Time" # convert this to GMT > (now.gmt <- as.POSIXlt(now,tz="GMT")) [1] "2003-07-29 22:23:58 GMT" # take difference > now-now.gmt Time difference of -5 hours Note that the difference

Full_Name: Erich Neuwirth Version: 2.3.1 OS: Windows XP, Linux Submission from: (NULL) (131.130.135.167) Converting Sys.Date() to a POSIX compliant time type in different ways produces inconsistent results: > Sys.date() [1] "2006-09-01" > as.POSIXct(Sys.Date()) [1] "2006-09-01 02:00:00 CEST" > as.POSIXlt(Sys.Date()) [1] "2006-09-01" >

Under R-2.2.1, a POSIXlt date created with "strptime" has an unknown Daylight Savings Time flag: > strptime(20051208, "%Y%m%d")$isdst [1] -1 This is true on both Linux (details below) and Windows. It did not occur under R-2.1.0. Any ideas? TIA! > Sys.getenv("TZ") TZ "" Version: platform = i686-pc-linux-gnu arch = i686 os = linux-gnu

This is a proposal for a simple partial solution to the date problems in R. It defines new classes, POSIXct0 and POSIXlt0, which are similar to their non trailing zero counterparts but have no timezone or daylight time. Internally they look like GMT times but they have their own methods. PROBLEM Problems with POSIX dates appear when you want to work with daily data or time data and just want

There is incompatibility between R strptime and musl libc. I posted about it on their mailing list, but they need more information I can't provide, so I'm forwarding the message here in hope R developers can help. Thanks. ---------- Forwarded message ---------- From: Rich Felker <dalias at libc.org> Date: Thu, Feb 4, 2016 at 2:07 PM Subject: Re: [musl] strptime() question To: Alba

Hello, sorry for my mail yesterday about the POSIXct problems. I was a bit tired and now I found out the real problem. When importing time data over a daylight saving time shift, R shifts two times. I don't now whether it is a bug or a (wrongly used) feature If you execute the following code: -------------- test<-c("31/03/2002 0:00", "31/03/2002 0:15",