similar to: A Question Re ISOdatetime

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

Hi ... I wonder if anyone can provide some insight into why the first three examples using the sunriset function (appended below, with results) give the correct answer, but the fourth generates and error. The first two use ISOdatetime with and without a time zone attribute, and the sunriset function returns the correct sunset time. The third and fourth adds 10 seconds to the ISOdatetime

The following three calls all produce the same result (my machine is in EST): > as.POSIXct(0, tz="", origin=ISOdatetime(1970,1,1,10,0,0)) [1] "1970-01-01 10:00:00 EST" > as.POSIXct(0, tz="EST", origin=ISOdatetime(1970,1,1,10,0,0)) [1] "1970-01-01 10:00:00 EST" > as.POSIXct(0, tz="GMT", origin=ISOdatetime(1970,1,1,10,0,0)) [1]

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 create a zooreg object that runs from Jan-1-2002 0:00 to Jun-1-2005 0:00... regts.start = ISOdatetime(2002, 1, 1, hour=0, min=0, sec=0, tz="") regts.end = ISOdatetime(2005, 6, 1, hour=0, min=0, sec=0, tz="") regts.zoo <- zooreg( NA, regts.start, regts.end, deltat=3600 ) Upon inspection: > regts.zoo[1:3] 2002-01-01 00:00:00 2002-01-01 01:00:00 2002-01-01 02:00:00

I think that there is a bug in the as.POSIXct function on Windows. Here is what I get on Win2000, Pentium III machine in R 1.8.1. > dd1 <- ISOdatetime(2003, 10, 26, 0, 59, 59) > dd2 <- ISOdatetime(2003, 10, 26, 1, 0, 0) > dd2 - dd1 Time difference of 1.000278 hours Now, the 26th of October was the day that change to the standard time occurred, so I suspect that this has

Hello, I at first thought this was a system or locale issue, but since it occurs on both Windows and Linux and only for 2004 (AFAIK) I report it. I have a problem with as.POSIXct for the hour between "2004-10-03 02:00:00 GMT" and "2004-10-03 02:59:59 GMT". In short, the 2 AM (GMT) hour in 2004 (but not in other years) is interpreted as 1 AM by strptime: (I use ISOdatetime

Conversion of a data frame to a matrix using as.matrix() when a column of the data frame is POSIXt and all other columns are numeric has changed in R 1.9.0 from R 1.8.1. The new behavior issues a warning message and converts to a character matrix. In R 1.8.1, such an object was converted to a numeric matrix. Here is an example. #### R 1.9.0 #### > foo <- data.frame(

Hi All, I am watching a strange behaviour of ISOdatetime. In my work computer, I get NA when I try to do > ISOdatetime(1995,03,26,2,0,0) [1] NA But on other dates and/or times (hour) works OK > ISOdatetime(1995,03,25,2,0,0) [1] "1995-03-25 02:00:00 GMT" In my home computer, I do not have this problem. I am running the same version of R (2.8.1 patched) on both machines, the

Dear list, I need to transform the DateTime of my GPS data from: "666.1751" into "yyyy/mm/dd hh:mm:ss" I have the following code: d$Date <- ISOdatetime(2009, 1, 1, 0, 0, 0, tz = "GMT")+d$Date*(24*3600) This gives me: 2010-10-29 04:12:09, which is wrong. It should be 2010-10-29 06:12:09 Another example: 418.3219 corresponds to: 2010-02-23 07:43:30, but it

Hi all, I am using ISOdatetime, and I just found out that when I do ISOdatetime(1995,03,26,2,10,0) (or any other value under minutes or seconds) I get NA This does not happen with the same time in other dates, nor with different hours in the same date. Any hint why this happens? Using R 2.8.1 under ESS/GnuEmacs under Windows XP Pedro -- View this message in context:

I've found several similar issues with write.table/read.table with Dates on this list, but trying to follow this advice I still get an error. First, I read in data from several files, constructing several date/time columns using ISOdatetime > str(Tall$Begin) 'POSIXct', format: chr [1:40114] "2005-10-02 00:00:00" "2005-10-02 00:00:00" ... > length(Tall$Begin)

I'm having problems entering dates and times around when daylight savings time starts. If I type (on R 1.8.1 on Gentoo Linux) > ISOdatetime(2004,4,4,0:4,0,0,"GMT") [1] "2004-04-03 19:00:00 EST" "2004-04-03 20:00:00 EST" [3] "2004-04-03 22:00:00 EST" "2004-04-03 22:00:00 EST" [5] "2004-04-03 23:00:00 EST" Giving the times

I am trying to do ephemeris calculations in R, which involves calculating an elapsed time. As illustrated below, difftime seems to have problems with my method, since the fractional day is sometimes the correct 0.5 and sometimes the incorrect 0.46. I am doing this on with R-2.6.1 on a powerpc-apple-darwin8.10.1 system. I get the same results for as.POSIXlt() instead of as.POSIXct(), but the

I'm searching for an r command that will notify me if I create a time that does not exist due to Daylight Savings Time. For example, if I run the following command on a windows machine > ISOdatetime(2010,03,14,2,10,0, tz = "") # My system time is set to the United States Central Time Zone [1] NA R returns NA, which is the behavior I want. However, if I run the same command on a

Hello, I have been trying to plot correctly a graph for 2 month now, with no success.I want to put a grid, adjusted on the X axis tickers. Here is the way I build my X-Axis and my grid: grid(11, NULL, col="grey40") axis(2) # build the tickers on the beginning of each monthticks.at <- seq(ISOdatetime(lastYear, 01, 01, hour=0, min=0, sec=0, tz="GMT"),

Hello! I am trying to compute minimal time on some data like this: mt<-tapply(mrsh$time1,list(mrsh$var1,mrsh$var2),min): a b 145 1054800600 1054789800 340 1054804500 1054794600 349 1054820400 1054792800 55 1054800600 1054789200 57 1054814100 1054791000 78 1054822200 1054790400 843

Hello, I have got the following problem: > setwd("C:/temp") > library(xlsReadWrite) > MyData <- read.xls(file="Mappe1.xls", colNames = TRUE,dateTimeAs = "isodatetime") > attach(MyData) > MyData name value times 1 A1 2 2006-05-12 2 A2 3 2006-05-16 3 A3 1 2006-05-12 4 A4 4 2006-05-12 5 A5 2

Hello, I'm trying to develop a box plot of time series data to look at the range in the data values over the entire period of record. My data initially starts out as a list of hourly data, and then I've been using this code to make this data into the final ts array. # Read in the station list stn.list <- read.csv("/home/kbennett/fews/stnlist3", as.is=T, header=F) # Read in

Hi, is there an R function to convert unixtime to one of the R time formats (using chron or POSIXct)? Example data: unixtime year month day hour 1183377301 2007 7 2 13 I would like to only use the first column. If such a function does not exist: What would be a good input format for R (I could parse the input using AWK or other GNU/Linux tools). TIA,