If the problem is that you have a vector of dates, a vector of times and a vector of data and you want to create a data frame with one POSIXct column and one column of data then try this:
dd <- c("01/22/2008", "02/13/2008") tt <- c("01:01:00", "23:01:12") dat <- 1:2 data.frame(dt = strptime(paste(dd, tt), "%m/%d/%Y %H:%M:%S"), dat) # if you don't need subsecond data or time zones you could use chron library(chron) data.frame(dt = chron(dd, tt), dat) If this is intended to be a time series you might want to look at the zoo package. It has three vignettes that give more info. On Feb 17, 2008 11:54 PM, Bo Zhou <[EMAIL PROTECTED]> wrote: > Hi Gabor, > > I'm using this code but it doesn't work for me > > > strptime2<-function (date,time) as.POSIXct(strptime(paste(date,time), > "%m/%d/%Y %H:%M:%S")) > > dt=mapply(strptime2, "01/01/2008", "00:00:00", SIMPLIFY=FALSE, > USE.NAMES=FALSE) > > df=data.frame(X1=dt,X2=1) > > dt > [[1]] > [1] "2008-01-01 Eastern Standard Time" > > > df > structure.1199163600..class...c..POSIXt....POSIXct....tzone...... X2 > 1 2008-01-01 1 > > Here df looks very wrong to me. > > So I tested this code: > > > df2=data.frame(X1=as.POSIXct(Sys.time()),X2=1) > > df2 > X1 X2 > 1 2008-02-17 23:43:08 1 > > class(df2$X1) > [1] "POSIXt" "POSIXct" > > Ah this worked as I expected. > > So some tweaking here - SIMPLIFY is set TRUE now: > > > strptime2<-function (date,time) as.POSIXct(strptime(paste(date,time), > "%m/%d/%Y %H:%M:%S")) > > dt=mapply(strptime2, "01/01/2008", "00:00:00", SIMPLIFY=TRUE, > USE.NAMES=FALSE) > > df=data.frame(X1=dt,X2=1) > > df > X1 X2 > 1 1199163600 1 > > class(df$X1) > [1] "numeric" > > Hmm... it worked, but not in a way I wanted. The class info is missing. > > So how to get the result like this below? I do need that mapply + > strptime(paste), cos my CSV file is formatted in that way! > > > df2 > X1 X2 > 1 2008-02-17 23:43:08 1 > > class(df2$X1) > [1] "POSIXt" "POSIXct" > > > Any insight? > > Cheers, > > Bo > > > > > Date: Sun, 17 Feb 2008 15:53:28 -0500 > > From: [EMAIL PROTECTED] > > To: [EMAIL PROTECTED] > > Subject: Re: [R] How to make a vector/list/array of POSIXlt object? > > CC: r-help@r-project.org > > > > > > Normally one uses POSIXct rather than POSIXlt for storage. See R News 4/1 > for > > more info on date and time classes. > > > > On Feb 17, 2008 3:45 PM, Bo Zhou <[EMAIL PROTECTED]> wrote: > > > > > > 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] "0007-07-12 13:20:01 GMT" > > > > dtt[1]=t > > > Warning message: > > > In dtt[1] = t : > > > number of items to replace is not a multiple of replacement length > > > > class(dtt) > > > [1] "list" > > > > class(t) > > > [1] "POSIXt" "POSIXlt" > > > > unclass(t) > > > $sec > > > [1] 1 > > > > > > $min > > > [1] 20 > > > > > > $hour > > > [1] 13 > > > > > > $mday > > > [1] 12 > > > > > > $mon > > > [1] 6 > > > > > > $year > > > [1] -1893 > > > > > > $wday > > > [1] 4 > > > > > > $yday > > > [1] 192 > > > > > > $isdst > > > [1] 0 > > > > > > attr(,"tzone") > > > [1] "GMT" > > > > > > > > > > > > Seems like POSIXlt is matrix in this case. > > > > > > Any suggestions? > > > > > > Cheers, > > > > > > B > > > _________________________________________________________________ > > > [[elided Hotmail spam]] > > > > > > [[alternative HTML version deleted]] > > > > > > ______________________________________________ > > > R-help@r-project.org mailing list > > > https://stat.ethz.ch/mailman/listinfo/r-help > > > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > > > and provide commented, minimal, self-contained, reproducible code. > > > > > ________________________________ > Need to know the score, the latest news, or you need your Hotmail(R)-get your > "fix". Check it out. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.