Using strptime() and other functions for dates has been very helpful with the kind of data I often work with. However, I haven't found out how time as such should be specified. All my attempts result in time *and* date:>treatment_time<-c("01:02:03","02:03:04") # hours:minutes:seconds >time.2<-strptime(treatment_time,format="%H:%M:%S")>time.2[1] "1900-01-01 01:02:03" "1900-01-01 02:03:04" Why the 1900-...? I had hoped for some easy conversion from time to numeric data and possibly back. Assistance would be appreciated. Robert
On Tue, 30 May 2006, Robert Lundqvist wrote:> Using strptime() and other functions for dates has been very helpful with > the kind of data I often work with. However, I haven't found out how time > as such should be specified. All my attempts result in time *and* date: > >> treatment_time<-c("01:02:03","02:03:04") # hours:minutes:seconds >> time.2<-strptime(treatment_time,format="%H:%M:%S") > >> time.2 > [1] "1900-01-01 01:02:03" "1900-01-01 02:03:04" > > Why the 1900-...? I had hoped for some easy conversion from time to > numeric data and possibly back. Assistance would be appreciated.You asked to print a datetime object of class POSIXlt, and unspecified fields are set to their earliest values. But printing is only part of the story. What do you actually want from this? 3600*time.2$hour + 60*time.2$min + time.2$sec gives you the number of seconds since midnight, for example. See ?DateTimeClasses -- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
Try using the "times" class in the chron package.> library(chron) > times(c("01:02:03","02:03:04"))[1] 01:02:03 02:03:04 On 5/30/06, Robert Lundqvist <Robert.Lundqvist at ltu.se> wrote:> Using strptime() and other functions for dates has been very helpful with > the kind of data I often work with. However, I haven't found out how time > as such should be specified. All my attempts result in time *and* date: > > >treatment_time<-c("01:02:03","02:03:04") # hours:minutes:seconds > >time.2<-strptime(treatment_time,format="%H:%M:%S") > > >time.2 > [1] "1900-01-01 01:02:03" "1900-01-01 02:03:04" > > Why the 1900-...? I had hoped for some easy conversion from time to > numeric data and possibly back. Assistance would be appreciated. > > Robert > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html >
Hi Which version of R do you use? Version 2.3.1 beta (2006-05-23 r38179)> treatment_time<-c("01:02:03","02:03:04") > strptime(treatment_time,format="%H:%M:%S")[1] "2006-05-30 01:02:03" "2006-05-30 02:03:04"> ttt<-strptime(treatment_time,format="%H:%M:%S")For changing format of POSIX variables use format> format(ttt, "%H:%M")[1] "01:02" "02:03" Maybe also consult locale setting. HTH Petr On 30 May 2006 at 14:16, Robert Lundqvist wrote: To: r-help at stat.math.ethz.ch From: Robert Lundqvist <Robert.Lundqvist at ltu.se> Date sent: Tue, 30 May 2006 14:16:29 +0200 Subject: [R] Time rather than dates? Send reply to: Robert.Lundqvist at ltu.se <mailto:r-help-request at stat.math.ethz.ch?subject=unsubscribe> <mailto:r-help-request at stat.math.ethz.ch?subject=subscribe>> Using strptime() and other functions for dates has been very helpful > with the kind of data I often work with. However, I haven't found out > how time as such should be specified. All my attempts result in time > *and* date: > > >treatment_time<-c("01:02:03","02:03:04") # hours:minutes:seconds > >time.2<-strptime(treatment_time,format="%H:%M:%S") > > >time.2 > [1] "1900-01-01 01:02:03" "1900-01-01 02:03:04" > > Why the 1900-...? I had hoped for some easy conversion from time to > numeric data and possibly back. Assistance would be appreciated. > > Robert > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.htmlPetr Pikal petr.pikal at precheza.cz