Hi Joshua, I was attempting to work with your code on the larger datasets, which I have to read in with 'read.table', but I've apparently missed something. When I attempt to massage the data.frame a bit in the code below, as.POSIXct drops the time component which then precludes use of xts. I think you'll see what I mean (the rdb file is a text file containing the data, which is attached to the post):
library(xts) Q_hourly<-read.table("C:/temp/07130500_BelowJM_q.rdb",skip=59,col.names=c('date','time','tz','Q','rating','unknown'),colClasses=c("character","character","character","numeric","character","character")) notice that Q_hourly[1,] # date time tz Q rating unknown #1 19981001 000000 MDT 326 3 A Q_hourly[2,] # date time tz Q rating unknown #2 19981001 001500 MDT 326 3 A and paste(strptime(Q_hourly[1,1],"%Y%m%d")," ",format(strptime(Q_hourly[1,2],"%H%M%S"),format="%H:%M:%S"),sep='') #[1] "1998-10-01 00:00:00" but for some reason, the time stamp is dropped in the following, which breaks the call to xts (I think) as.POSIXct(paste(strptime(Q_hourly[1,1],"%Y%m%d")," ",format(strptime(Q_hourly[1,2],"%H%M%S"),format="%H:%M:%S"),sep=''),format="%Y-%m-%d %H:%M:%S",tz="") #[1] "1998-10-01 PDT" The Q_use data.frame I'm building here should come out exactly http://r.789695.n4.nabble.com/file/n4643206/07130500_BelowJM_q.rdb 07130500_BelowJM_q.rdb the same as in my original post (above), but I can't seem to seem to force the preservation of the time stamp even though I've explicitly stated the format I want to be stored (...format="%Y-%m-%d %H:%M:%S"). Any ideas? xQ <- xts(Q_use["Q"], Q_use$date) #Error in `[.data.frame`(x, indx) : undefined columns selected -- View this message in context: http://r.789695.n4.nabble.com/calculate-within-day-correlations-tp4643091p4643206.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.