In the first case: mdat$value<-.POSIXct(mdat$value,tz="EST") mdat$value[1:3] #[1] "2012-01-01 01:00:00 EST" "2012-01-01 02:00:00 EST" #[3] "2012-01-01 03:00:00 EST" mydata$dd1[1:3] #[1] "2012-01-01 01:00:00 EST" "2012-01-01 02:00:00 EST" #[3] "2012-01-01 03:00:00 EST" A.K.
----- Original Message ----- From: John Kane <jrkrid...@inbox.com> To: r-help@r-project.org Cc: Sent: Monday, May 13, 2013 1:36 PM Subject: [R] melt in reshape2 destroying dates? When I melt a data frame with some dates I am getting some strange results. I seem to lose the date format with POSIXct and get a row of zeros with POSIXlt Any suggestions as to what I am messing up? Code and data below. Thanks, John Kane Kingston ON Canada mydata <- structure(list(dd1 = structure(c(1325397600L, 1325401200L, 1325404800L, 1325408400L, 1325412000L, 1325415600L, 1325419200L, 1325422800L, 1325426400L, 1325430000L, 1325433600L, 1325437200L, 1325440800L, 1325444400L, 1325448000L, 1325451600L, 1325455200L, 1325458800L, 1325462400L, 1325466000L), class = c("POSIXct", "POSIXt"), tzone = ""), dd2 = structure(c(1325426400, 1325412000, 1325426400, 1325422800, 1325422800, 1325426400, 1325433600, 1325437200, 1325455200, 1325458800, 1325451600, 1325458800, 1325466000, 1325466000, 1325476800, 1325476800, 1325480400, 1325466000, 1325480400, 1325491200), class = c("POSIXct", "POSIXt"), tzone = ""), emp = structure(c(1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L), class = "factor", .Label = c("part-time", "self-employed")), period = 1:20), .Names = c("dd1", "dd2", "emp", "period"), row.names = c(NA, -20L), class = "data.frame") library(lubridate) library(reshape2) str(mydata) mdat <- melt(mydata, id=c("emp","period")) str(mdat) # alternatively mydata$dd1 <- as.POSIXlt(mydata$dd1) mydata$dd2 <- as.POSIXlt(mydata$dd2) str(mydata) mdat <- melt(mydata, id=c("emp","period")) str(mdat) ____________________________________________________________ TRY FREE IM TOOLPACK at http://www.imtoolpack.com/default.aspx?rc=if5 Capture screenshots, upload images, edit and send them to your friends through IMs, post on Twitter®, Facebook®, MySpace™, LinkedIn® – FAST! ______________________________________________ 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. ______________________________________________ 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.