similar to: seq.POSIXt() with short time intervals

seq.default() tests for the relative range of the from and to arguments (see excerpt below) and returns from (only) when the relative range is small. The problem is that "small" is too large. Also undocumented. At 17:25 +0000 3/26/02, ripley@stats.ox.ac.uk wrote: >On Tue, 26 Mar 2002, Don MacQueen wrote: > >> I was surprised when seq.POSIXt() returned a single value

I have written a set of functions for POSIXt objects that I would like to offer for consideration for use in base R. They augment and extend existing functions. Briefly, ## pretty.ct function(x,specs=pretty.ct.specs) ## round.ct function(x, tstr='1 min' ) ## axis.ct function(side,x,specs=NULL,...) ## parse.timeint function(dv) ## parse.tstr

Hi all, I need to compare time series data files of different time formats. I had no problems with text format using strptime. But how can I convert datetime numbers from Excel (days since 30.12.1899 00:00:00) into POSIXt objects? For example 29770.375 should be converted to "03.07.1981 09:00:00" I tried the following code and encountered strange results: t1-t0 gives 29770.33

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

For certain values, round.POSIXt(tm,'day') does not round to midnight as documented. The reason is that trunc.POSIXt() does not adjust the value of the isdst element. Assuming my assessment of the reason is correct, I have a potential solution to offer. Additional discussion is in bug report #1543. -Don > x <- c(as.POSIXct('2001-4-1 3:15'),as.POSIXct('2001-5-2

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

There seems to be a problem in the way `+` is dispatched for POSIXt/difftime (R 2.8.0 Windows). With the following definitions: t0 <- as.POSIXct('2009-01-01 00:00') halfhour.mins <- as.difftime(30,units='mins') I would have thought that the straightforward answer to Suresh's question would be something like t0 + halfhour.mins * (0:47) And indeed, if we

I am trying to extract only the winters (defined to be 01-Dec through 28-Feb) of daily data from 1948-2002. There are 90 days in each winter season. I wrote the following code to gather the winter dates into a single vector: DJF <- NULL for(year in 1949:1999) { temp.begin <- strptime(paste("01/12", year-1, sep="/"), "%d/%m/%Y") temp.end <-

I am finding that axis.POSIXct uses the local timezone for deciding where to put tic marks, even if the data being plotted are in another time zone. The solution is to use attr() to copy from the 'x' (provided as an argument) to the 'z' (used for the 'at' locations). I have pasted my proposed solution in section 1 below (as a diff). Then, in section 2, I'll put some

I think the following examples illustrate the crux of the matter (version and OS info are below). The problem has to do with the transition from standard time to daylight savings time. My timezone, US/Pacific, has two parts: standard time (PST) 8 hours behind GMT and daylight savings time (PDT) 7 hours behind GMT. The transition takes place this year on 7 April at 02:00, when 02:00 is

I am still experiencing problems with seq.POSIXt() missing off the last day of the series: > seq(as.POSIXct("2004-03-25"),as.POSIXct("2004-03-31"),by="DSTdays") [1] "2004-03-25 GMT Standard Time" "2004-03-26 GMT Standard Time" "2004-03-27 GMT Standard Time" [4] "2004-03-28 GMT Standard Time" "2004-03-29 GMT Daylight

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 decided my earlier email on this topic was rather long and wordy; here's a condensed version. I am sitting at a Solaris computer in the US/Pacific timezone. I have a file of data having times that includes the following three values 2002-4-7 1:30:00 GMT 2002-4-7 2:30:00 GMT 2002-4-7 3:30:00 GMT I have not been able to find a way to correctly convert these to either of the POSIX

Currently (R-1.4.1 as well as R-devel, according to http://stat.ethz.ch/R-alpha/R-devel/library/base/html/par.html), the html version of help(par) shows [...] lab A numerical vector of the form c(x, y, len) which modifies the way that axes are annotated. The values of x and y give the (approximate) number of tickmarks on the x and y axes and len specifies the label size. The default

Hi all, This summer I've been working with a grad student to bring more of the date time classes from JODA (http://joda-time.sourceforge.net/) into R. To make these work seamlessly with existing date time objects, we need to patch +.POSIXt. (The ruby community uses the term monkey-patching for this sort of ill-advised, by sometimes necessary, internal hackery, hence the title.) The problem is

I want to set up a simple Tk dialog interface to a function in R, such that when the "OK" button is pressed, the dialog window is destroyed and then R does its work on the data/parameters/whatever that were entered in the dialog. The function "test" below is a simple prototype. My problem: upon running test() and hitting "OK", R does its work (ie, computes

I can't reach r-project.org at the moment so cannot check whether this is a known bug. > version _ platform i386-pc-mingw32 arch x86 os Win32 system x86, Win32 status major 1 minor 3.0 year 2001 month 06 day 22 language R The

POSIXct/lt supports fractional seconds (see Sub-second Accuracy section of man page), but there seem to be some inconsistencies in their handling. Converting to POSIXlt and back does not give back the same time for times before the origin: > t0 <- as.POSIXct('1934-01-05 23:59:59.00001') > t0 [1] "1934-01-06 00:00:00 EST" # rounding issue, see below >

Times from seq.POSIXt come out wrong in AEST timezone around Feb 29 every leap year before 1970 (on Windows XP). According to help(DateTimeClasses), this is handled by "our own C code". > x <- as.POSIXct("1968-02-27") # tz="AEST" > x.gmt <- as.POSIXct("1968-02-27", tz="GMT") > data.frame( GMT=seq(x.gmt, by="day",

Hello, ?DateTimeClasses states that "one can add or subtract a number of seconds or a 'difftime' object from a date-time object, but not add two date-time objects." So, is the below expected behavior? > x <- Sys.time() > x [1] "2007-02-21 16:19:56 CST" > x + as.difftime("1","%H") [1] "2007-02-21 16:19:57 CST" Warning