similar to: Conversion a ts time to another class.

Dear all, Ive just started with R and I have question: how can you change a time from a ts object .i.e 2009.004 to "2009-01-01"? Is there any function for this? I tried around with as.Date... but it hasnt worked. Thank you beforehand. Chuse. [[alternative HTML version deleted]]

Dear R collegues, I am trying to change a ts time such as 2009.004 to a str or POSIX class "2009-01-01". Is there any function or method to do it?. Thank you beforehand. Chuse. [[alternative HTML version deleted]]

Dear R users, I have to calculate gamma functions for negative numbers beyond -171.4. e.x. gamma(-500.4) I got following: > gamma(-170.4) [1] -5.824625e-308 > gamma(-171.4) [1] 0 Warning message: underflow occurred in 'gammafn' I have tried to use a recursion getting values a little futher -180. How could I solve this problem? Thank you beforehand. Chuse.

Dear users, I tried to fit an AR(2) model to data. This the result: > arima(vw,c(3,0,0)) Call: arima(x = vw, order = c(3, 0, 0)) Coefficients: ar1 ar2 ar3 intercept 0.1052 -0.0102 -0.1203 0.0099 s.e. 0.0337 0.0339 0.0338 0.0018 sigma^2 estimated as 0.002934: log likelihood = 1293.16, aic = -2576.33 Now, ar2 is not significantly different from

Dear R collegues, I'd like to use the time-series facilities of R and I'm not sure how to set my dataset properly. I have monthly data, so the description could be: ts(data, start=c(1951,1), frequency= 12) However, the data is a matrix of years (rows) and months (columns), as follows: > s1 <- read.table("stdata.txt", header=TRUE) > s1[1:3, ] YEAR JAN FEB MAR APR

R 3.5.0 Is it intended that the Date method of as.POSIXct does not respect the tz parameter? I suggest changing as.POSIXct.Date to this: function (x, tz = "", ...) .POSIXct(unclass(x) * 86400, tz = tz) Currently, the best workaround seems to be using the character method if one doesn't want the default timezone (which is often an annoying DST timezone). This came up on

Hello, I am trying to calculate the autocovariance matrix for any general farima(p,d,q) with p,q > 1. Could anyone give an idea how to implement in R or if there is any package for this? thank you beforehand. Jose.

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

Dear All, what determines if a difference between POSIXct objects gets expressed in days or seconds? In the following example, it's sometimes seconds, sometimes days. as.POSIXct('2009-09-01') - as.POSIXct(NA) Time difference of NA secs c(as.POSIXct('2009-09-01'), as.POSIXct(NA)) - c(as.POSIXct('2009-09-01'), as.POSIXct('2009-08-31')) Time differences in

Windows-32 has a time structure called FILETIME, a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC). That is not a typo, the year is 1601. Does anyone have a clue(or algorhithm)for how this is converted to something a little more POSIX-like ? Thank you, Derek -- Derek N. Eder Gothenburg University VINKLA - Vigilance and Neurocognition

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

> 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

I am trying to use POSIX datetime objects rather than chron datetime objects but am having difficulty with POSIX in a time series. My question: Once a POSIXct vector is bound to a time series, is there a function to convert back to POSIXct? The following code demonstrates what I am trying to do. > ts(as.POSIXct(strptime(tmp,"%m/%d/%Y %H:%M:%S")),freq=1440) Time Series: Start =

What is the recommended class for time of day (independent of calendar date)? And what is the recommended way to get the time of day from a POSIXct object? (Not a string representation, but a computable representation.) I have looked in the man page for DateTimeClasses, in the Time Series Analysis Task View and in Spector's Data Manipulation book but haven't found these. Clearly I can

Hi * i've done my anova anlysis but now i need post-hoc test, are these included in R ? I've a Big problem, working with people that don't like to use command-line software (but prefer something like openoffice) does someone is trying to do a usable GUI for R ? i'm reading something on R commander SciView and others but all seem to be beta. I'd like to make possible to make

R developers, The "tzone" attribute is stripped from a POSIXct object when the subscript command is called ("[.POISXct"). This results in dates being printed in the locale specific format after a subscript operation is applied to a POSIXct object which has cause several problems for me in the past. Here is an example of this problem under R 1.9.1: > x <-

Full_Name: Bo Zhou Version: 2.6.1 (2007-11-26) OS: Windows XP Submission from: (NULL) (207.237.54.242) Hi, I found an arithmetic problem when I'm doing something with POSIXct The code to reproduce it is as follows (This is the recommended way of finding out time zone difference on R News 2004-1 Page 32 URL http://cran.r-project.org/doc/Rnews/Rnews_2004-1.pdf) a=Sys.time()

OK. What if I have a time series which is collected every Monday, please? What is the proper way to use the start option within the ts command in order to indicate that this is Monday data, please? Thanks again! Sincerely, Erin

Hello, I searched the archives but could not come to a solution. I have to two columns of information t_start_cdt looks like: > t_start_cdt[1:4] [1] "2003-07-09 11:02:25" "2003-07-09 11:10:25" "2003-07-09 11:30:25" [4] "2003-07-09 12:00:25" > class(t_start_cdt) [1] "POSIXt" "POSIXlt" t_end_cdt looks like: > t_end_cdt[1:4]

Inside of the anyNA() function, it will use the legacy any(is.na()) code if x is an OBJECT(). If x is a vector of POSIXct, it will be an OBJECT(), but it is also TYPEOF(x) == REALSXP. Therefore, it will skip the faster ITERATE_BY_REGION, which is typically 5x faster in my testing. Is the OBJECT() condition really necessary, or could it be moved after the switch() for the individual TYPEOF(x)