similar to: Length of a vector of POSIX objects reported incorrectly?

The manual entry for as.POSIX says this about time zone codes... Usage as.POSIXct(x, tz = "") tz A timezone specification to be used for the conversion... but it fails to mention what these "specifications" are. So far, I have tried... as.POSIX(x, tz="UTC") ... works, gives UTC times as.POSIX(x, tz="UTC") ... works, gives EST times as.POSIX(x,

# pure replication code at end > # These work > > Sys.time() + NA [1] NA > as.POSIXlt(Sys.time(), "GMT") + NA [1] NA > > class(Sys.time() + NA) [1] "POSIXt" "POSIXct" > class(as.POSIXlt(Sys.time(), "GMT") + NA) [1] "POSIXt" "POSIXct" > > x <- Sys.time() + NA > y <- as.POSIXlt(Sys.time(),

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]

> 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 having a series of problems using date time data that has been converted into a POSIXt and POSIXlt classes. I have hourly time series data from 1900 that has been converted from text data. I assume most of my problems come from a mis-underdanding of the POSIX class. My matrix named (aa) for this year is approx 8700 by 4. When I try to calculate the length of posit column ( which is the

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

For the r script below >datestr <- "01/01/2004" >as.POSIXct(as.Date(datestr, "%d/%m/%Y")) I get the following output "2003-12-31 18:00:00 Central Standard Time" Why is the date a day before. I guess its something to do with the time, but is there a way to get it to return 2004-01-01 instead? Thanks in advance... -Sandeep [[alternative HTML version

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]

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, I'm having a weird result with the length() function: >a [... omited ...] [9994] NA "2003-12-03 16:37:00" "2002-06-26 18:43:00" [9997] "2005-07-04 04:00:00" "2007-02-16 22:09:00" "2007-02-24 15:49:00" [10000] NA > length(LastModified) [1] 9 > length(c(LastModified)) [1] 9 I was expecting to get

Sorry to ask such a simple question, but I can't find the answer after extensive searching the docs and the web. How do you remove a component from a list? For example say you have: lst<-c(5,6,7,8,9) How do you remove, for example, the third component in the list? lst[[3]]]<-NULL generates an error: "Error: more elements supplied than there are to replace" Also,

When I do this (highly simplified example): plot(as.POSIXct(c("1984-01-01","1984-01-02")), c(1,2), col=2) I get a partially red (col=2) x-axis between and including the first and last tick marks. Otherwise ok. Only happens with POSIXct or POSIXlt dates. Also, POSIX dates cannot be used on the y-axis? POSIXlt gives an error, and POSIXct is unformatted. Bruce Using X11

Hi, I'm working with objects of classes "Date","POSIXlt" and "POSIXct" and still having some Date/Time-related concepts unclear. In the documentation of "as.Date" one can find: "The 'as.Date' methods accept ... '"POSIXlt"' and '"POSIXct"'. (The last are converted to days by ignoring the time after

When I try to do linear interpolation between financial contracts with maturities on different dates in different months I have come across some behavior I haven't seen before. I have a data frame in R which is loaded from an access database so I can't provide a working example. It was loaded using this code: > dbPath <- "H:/pathToDB/DB.mdb" > channel <-

Hi, I have two data sources. One records time in PST time zone, the other in GMT. I want to compute the difference between the two, but don't see how. Here is an example where I compute time difference between identical times each (meant to be) relative to its time zone. > as.POSIXlt("2000-05-10 10:15:00", "PST") - as.POSIXlt("2000-05-10 10:15:00",

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

converting a POSIX class variable to a date class is easy. dates<-as.Date(x) #where X is of class POSIX How does one do that to all columns in a data frame that are of POSIX class and leave all the other columns (integers, factors) as is. Feel free to reply with just one or two buzzwords that I could then search for to find how to do it. Farrel Buchinsky

I have a problem ordering by descending magnitude a POSIXt object. Can someone help please and let me know how to work around this. My goal is to be able to order my data by DATE and then by descending TIME. I have tried to include as much info as possible below. The problem stems from trying to read in times from a CSV file. I have converted the character time values to a POSIXt object using the

Hallo all just a small question I did not find an answer in help pages. Is it possible to use identify() after plotting with plot.POSIX to label points and/or to find out some points? Thanks a lot. Best regards Petr Pikal petr.pikal at precheza.cz p.pik at volny.cz

Hi, Matplot works with x being Date class but not POSIXt. Here is the example with R version 2.5.0 Under development (unstable) (2006-12-06 r40129) Example: x <- Sys.Date() - c(1:10) y <- cbind(1:10, 10:1) class(x) ## [1] "Date" matplot(x, y) x <- strptime(as.character(x), format="%Y-%m-%d") ## [1] "POSIXt" "POSIXlt" matplot(x, y) Error in