[R] Applying strptime() to a data set or array

2006-03-06 Thread Andrew Athan
I'm sure this is just the result of a basic misunderstanding of the syntax of R, but I am stumped. A - read.table(file=sumByThirtyMinute.csv,sep=,,col.names=c(date,pandl)) A now consists of thousands of rows, but A$date is a string... ... 3183 2006-02-28 12:00:00548.470 3184 2006-02-28

Re: [R] Applying strptime() to a data set or array

2006-03-06 Thread Jacques VESLOT
maybe you need to transform A$date to character: A$date - strptime(as.character(A$date), ...) see also: ?ISOdatetime Andrew Athan a écrit : I'm sure this is just the result of a basic misunderstanding of the syntax of R, but I am stumped. A -

Re: [R] Applying strptime() to a data set or array

2006-03-06 Thread Andrew Athan
A$date is already a string, as read from the file. I tried it anyway, for you... A$date-strptime(as.character(A$date),%Y-%m-%d %H:%M:%s) Error in $-.data.frame(`*tmp*`, date, value = list(sec = c(0, 0, : replacement has 9 rows, data has 3198 A. Jacques VESLOT wrote: maybe you

Re: [R] Applying strptime() to a data set or array

2006-03-06 Thread Gabor Grothendieck
POSIXct, not POSIXlt, are used in data frame columns. See ?POSIXct where this is mentioned and try: A$date - as.POSIXct(A$date) Also be sure to read R News 4/1 for more about dates and times. On 3/6/06, Andrew Athan [EMAIL PROTECTED] wrote: I'm sure this is just the result of a basic

Re: [R] Applying strptime() to a data set or array

2006-03-06 Thread Andrew Robinson
Try prepending as.POSIXct A[,1] - as.POSIXct(strptime(A$date,%Y-%m-%d %H:%M:%s)) A. On Mon, Mar 06, 2006 at 11:58:01PM -0500, Andrew Athan wrote: I'm sure this is just the result of a basic misunderstanding of the syntax of R, but I am stumped. A -

Re: [R] Applying strptime() to a data set or array

2006-03-06 Thread Jacques VESLOT
it's probably a factor, not a string vector... so i would do as.vector or as.character - but it may be not necessary ! as.POSIXct(strptime(as.vector(A$date),...)) or: seq( from = ISOdate(2006,02,28, 12, 0, 0, tz=), to = ISOdate(...), by=30 min) Andrew Athan a écrit : A$date is already

Re: [R] Applying strptime() to a data set or array

2006-03-06 Thread Prof Brian Ripley
The simplest way to do this is to use colClasses to specify that you want POSIXct: see the documentation for read.table. strptime returns an object of class POSIXlt (a list of length 9), and you cannot put that in a data frame. So the issue is not that stated in the subject line: apply