similar to: Date conversion with as.POSIXct and as.POSIXlt (PR#9196)

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

Hi. This feels like a bug to me, or at least an undocumented feature, but I thought I'd see what people here thought of it. Consider a POSIXlt object like this one: > a <- as.POSIXlt ("2011-01-23 12:45:45") > class (a) [1] "POSIXlt" "POSIXt" Fine. Now, if I do some arithmetic on that object, the result is converted to POSIXct. > class (a

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 wrote a R script say called computeCovarMatrix.R and i want to call and run this piece from Excel visual basic. does anyone know how to do that? thanks, KZ [[alternative HTML version deleted]]

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"))

Hi all I was wondering whether there has ever been an update on the rownames and colnames behaviour as described by Eric below? I still get the same behaviour, exactly as described by Eric, on my WinXP installation of R-2.3.0. I also posted a message to r-help on Friday but looking through the online archives it seems to have not made it to the list. I would agree with Eric that a consistent

From POSIXct to numeric and back with time zone I am running regressions on data which has time series with different time resolution. Some data has hourly resolution, while most has either daily or weekly resolution. Aggregation is used to make the hourly data daily, while liner interpolation is used to find daily data from the weekly time series. This data manipulation requires some careful

Hello, Following Dirk's post here: https://github.com/Rdatatable/data.table/issues/1619 we would like to clarify if this is the right behaviour, and if so, the rationale behind it. Here's the summary (thanks to Dirk and Joshua): Sys.setenv("TZ"="America/Chicago") dates = as.Date("2016-03-02") + (0:3)*7 # four Wednesdays # [1] "2016-03-02"

Hi R users: This is a very strange problem: Why this instruction shows me NA?, and any other date shows me that error! as.POSIXct(strptime("1992-5-3",format="%Y-%m-%d")) This is my R version on windows 7. "R version 2.13.1 Patched (2011-08-25 r56794)" Thank you for your help.

Dear R users, I've just posted a similar question about Illustrator. This time I would like to export the results of my statistic tables and my dataframes into Excel files. Up to now I've used write.csv(), but I have to resave every file in .xls in Excel. I would like to know if there is a function or package to export directly into *.xls. I have found xlsReadWrite which would be

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

I noticed something surprising (in R 2.2.1 on WinXP) According to the documentation, rownames and colnames are character vectors. Assigning a vector of class POSIXct or POSIXlt as rownames or colnames therefore is not strictly according to the rules. In some cases, R performs a reasonable typecast, but in some other cases where the same typecast also would be possible, it does not. Assigning a

I noticed something surprising (in R 2.2.1 on WinXP) According to the documentation, rownames and colnames are character vectors. Assigning a vector of class POSIXct or POSIXlt as rownames or colnames therefore is not strictly according to the rules. In some cases, R performs a reasonable typecast, but in some other cases where the same typecast also would be possible, it does not. Assigning a

some of you might be interested. i just uploaded the first release of my r-excel interface package to CRAN. it is in contributed extensions nonstandard extensions erich neuwirth -- Erich Neuwirth, Computer Supported Didactics Working Group Visit our SunSITE at http://sunsite.univie.ac.at Phone: +43-1-4277-38624 Fax: +43-1-4277-9386

some of you might be interested. i just uploaded the first release of my r-excel interface package to CRAN. it is in contributed extensions nonstandard extensions erich neuwirth -- Erich Neuwirth, Computer Supported Didactics Working Group Visit our SunSITE at http://sunsite.univie.ac.at Phone: +43-1-4277-38624 Fax: +43-1-4277-9386

Hi Ben Thanks for your answer I have already tried this, as well as x <- as.POSIXct(strptime("2002-02-02 02:02", "%Y-%m-%d %H:%M")) It works! But it does not fix it widely for all tests used during the "make check" step at compile time. Unless I patch all of them. There is something with localtime but I cannot find what. On another machine with another

I have a big contingency table, approximately of size 60*2*500*500, and I need to count the number of cells containing a count of 1 for each of the factors values defining the first dimension. Here is my attempt: tab1<-with(pisa1,table(CNT,GENDER,ISCOF,ISCOM)) tab2<-apply(tab1,1:4,function(x)ifelse(sum(x)==1,1,0)) tab3<-apply(tab2,1,sum) Computing tab2 is very slow. Is there a faster

In trying to use as.Date(), I've come across the conversion of POSIXlt to POSIXct when a POSIXlt variable is included in a data frame: my_POSIX <- strptime(c("11-09-2006", "11-10-2006", "11-11-2006", "11-12-2006", "11-13-2006"), "%m-%d-%Y") str(my_POSIX) my_Date <- as.Date(my_POSIX) str(my_Date) data <- format(my_Date)

I'm trying to generate POSIXct times in a call to a C function. However, I'm having trouble generating times with the proper offset from UTC. Can anyone offer any help with this issue? I've looked at R-2.0.1/src/main/datetime.c, but I was not able to find an example that I could easily pull from that file. Thanks in advance, Whit Here is my example in C: #include <stdio.h>

To Whom It May Concern: The following appears to be a bug in the way POSIXct dates are formated. The example is forced, but occurs naturally when importing Excel type dates (where fractional part is fraction of a day) and small rounding errors result. As shown, looking at the POSIXct class, it looks as if both times are 16:11:03 (truncation) Looking at as.numeric.POSIXct, it looks as if