hi again I will try this time to explain my problem clearly I have the following data from the file skiing.csv (3 first rows)
protokollid date start end 1 4 2/23/2009 8:50:10 15:17:30 2 4 2/24/2009 9:47:00 13:52:25 3 5 3/22/2009 8:51:25 12:00:05 I have the following script library(chron) skiers=read.csv("skiing.csv") strptime("08:50:10","%H:%M:%S") start=times(skiers[,3]) strptime(start,"%H:%M:%S") end=times(skiers[,4]) strptime(end,"%H:%M:%S") #calc lenght of the route length.route=end-start #calc medians median(start) median(length.route) Then I want to do a box plot of the staring time when I use: boxplot(start) this error appears: Warning message: In is.na(x) : is.na() applied to non-(list or vector) of type 'NULL' when I try to convert start as POSIXct > start=as.POSIXct(start) Error in as.POSIXct.default(start) : do not know how to convert 'start' to class "POSIXlt" and when I try to convert skiers[,3] as POSIXct > skiers[,3]=as.POSIXct(skiers[,3]) Error in as.POSIXlt.character(as.character(x)) : character string is not in a standard unambiguous format start is of "times" class and skiers[,3] of "factor" class I want to do a boxplot of the starting time of my data, which reflect the median " 08:36:45", and all O get in the y axis are decimal numbers :( Help please Best regards Maria Stauss -- View this message in context: http://n4.nabble.com/HELP-boxplot-for-time-class-tp949154p949154.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.