similar to: as.POSIXct problem?

> x<-as.POSIXct("1970-1-1", tz="UTC")-.5 > y<-as.POSIXct("1970-1-1", tz="UTC")+.5 > x==y [1] FALSE # of course but x and y "appear" to be the same when formatted, even with extra precision: > format(x, format="%Y-%m-%d %H:%M:%OS2") [1] "1970-01-01 00:00:00.50" > format(y, format="%Y-%m-%d

Dear R-users, I use unlist of POSIX dates to extract the year, hour etc. With that I can search for files in my database which are in the form 'yyyymmddhh_synops.txt' However, I get stucked during midnight where unlist just gives NA's. The script is given below, the problem accurs at acc.period[16] (midnight). However when I write out the character, unlist works well. But

Delving into the murky world of dates and times I found this: dates <- c("02/27/92", "02/27/92", "01/14/92", "02/28/92", "02/01/92") > times <- c("23:03:20", "22:29:56", "01:03:30", "18:21:03", "16:56:26") > x <- paste(dates, times) > z <- strptime(x, "%m/%d/%y

Dear useRs, How come the first attempt to sort a POSIXt vector fails (Error: non-atomic type in greater), while the second succeeds? (Code inserted below.) The documentation says that POSIXt is used to allow operations such as subtraction, so I'd expect sorting to work. Is this perhaps an OS issue? (I run R 2.0.1 on Win xp.) Thank you, b. #------------code test <- c("2005-02-08

Hi Guys, I'm cooking up my time series code. I want a data frame with first column as timestamp in POSIXlt format. I hit on this the problem of how to create an array/list/vector of POSIXlt objects. Code is as follows > dtt=array(dim = 2) > t=as.POSIXlt( strptime("07/12/07 13:20:01", "%m/%d/%Y %H:%M:%S",tz="GMT")) > dtt [1] NA NA > t [1]

> is.na(strptime("5/2/1992", format="%m/%d/%Y")) [1] FALSE > is.na(strptime("5/3/1992", format="%m/%d/%Y")) [1] TRUE Any idea what's going on with this? Running strptime against all dates from around 1946, only 5/3/1992 was converted as "NA". Even stranger, it still seems to have a value associated with it (even though is.na thinks

Hi, I have a dataframe column of the form v<-c("Fri Feb 05 20:00:01.43000 2010","Fri Feb 05 20:00:02.274000 2010","Fri Feb 05 20:00:02.274000 2010","Fri Feb 05 20:00:06.34000 2010") I need to convert this to datetime form. I did the following.. lapply(v,function(x){strptime(x, "%a %b %d %H:%M:%OS %Y")}) This gives me a list that looks like

In the following, can anyone tell me why length(eee) returns 9? I was expecting 15398, and when I try to add this vector to a data frame with that many rows, it fails complaining that the vector is of length 9. In what I thought was an identical situation with a related dataset, the same code worked as expected. > length(fff) [1] 15398 > str(fff) int [1:15398] 20010102 20010102

Have you noticed any problems with big dates (>=1/1/2040) in R? Here is the bit of code that I'm having trouble with: > test.date <- strptime("1/1/2040",format="%m/%d/%Y") > > unlist(test.date) sec min hour mday mon year wday yday isdst 0 0 0 1 0 140 0 0 0 > > date.plus.one <- as.POSIXct(test.date) +

Full_Name: George N. White III Version: 1.9.0 OS: Irix 6.5.21m Submission from: (NULL) (142.176.61.212) R-1.9.0 built using the SGI MIPSPro compilers Installation directory: /usr/local C compiler: c99 -OPT:IEEE_NaN_inf=ON -mips4 -n32 -O3 -OPT:Olimit_opt=on C++ compiler: CC -OPT:IEEE_NaN_inf=ON -mips4 -n32 -O3 -OPT:Olimit_opt=on -LANG:std Fortran compiler:

Although the documentation is somewhat sketchy, I() can be used to create objects of class AsIs: > I("a") [1] "a" attr(,"class") [1] "AsIs" "character" > I(4) [1] 4 attr(,"class") [1] "AsIs" "numeric" > I(4 + 0i) [1] 4+0i attr(,"class") [1] "AsIs" "complex" > This

R 2.6.1 on a Thinkpad T60 running up-to-date Gentoo: Despite the documentation, which says: 'strftime' is an alias for 'format.POSIXlt', and 'format.POSIXct' first converts to class '"POSIXlt"' by calling 'as.POSIXlt'. Note that only that conversion depends on the time zone. strftime fails on POSIXct objects: > foo <-

In attempting to build R using rpmbuild --rebuild R-2.1.0-0.fdr.2.fc3.src.rpm on a fairly up-to-date RedHat 9 system (that is, with patches installed through May 1 2004), it failed at the make check-all step. The problem was reproducible by going into the tests directory and make test-Segfault The last lines of the saved file no-segfault.Rout.fail are > > ## c.POSIXct : > >

hello, I have a vector of factors > str(rcptdt) Factor w/ 51 levels "1/10/03","1/13/03",..: > length(rcptdt) [1] 87 which i want to convert to class POSIXlt to extract the day, so: a1<-format(rcptdt,"%m/%d/%y") > length(a1) [1] 87 and: a2<-strptime(a1, "%m/%d/%y") str(a2) `POSIXlt', format: chr [1:87] "2002-04-18"

Arrays of POSIXlt dates always return a length of 9. This is correct (they're really lists of vectors of seconds, hours, and so forth), but other methods disguise them as flat vectors, giving superficially surprising behaviour: strings <- paste('2009-1-', 1:31, sep='') dates <- strptime(strings, format="%Y-%m-%d") print(dates) # [1]

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

Hi all; I've already send a similar e-mail to the list and Prof. Brian Ripley answered me but my doubts remain unresolved. Thanks for the clarification, but perhaps I wasn't clear enough in posting my questions. I've got a postgres database which I read into R. The first column is Timestamp with timezone, and my data are already in UTC format. An 'printed' extract of R

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

Dear list: working with date/times I have come across a problem that ISOdate and ISOdatetime are too slow on large vectors of data. I was surprised just until I looked at the implementation and the man page: "ISOdatetime and ISOdate are convenience wrappers for strptime". In other terms, they convert data to character representation first in order to create a POSIXlt object that is then