On Mon, 2007-12-03 at 13:21 -0800, Judith Flores wrote: > Hi, > > I have a vector in a data frame that looks > something like this: > > day<-c('Day -1','Day 6','Day 10') > > > This vector specifies the order in which several > panel will appear in a lattice plots. But the order in > which such plots will appear will be the following: > Day -1, Day 10, Day 6. Which makes sense, but I cannot > name the Days like this: Day -01,Day 10, Day 06, which > would put the levels in the order I want them to be. > > Now, this vector won't always have the same values, > it could be: > > day<-c('Day -1, 'Day 2','Day 14') > > So I cannot set the levels manually: > > levels(day)<-c('Day -1', 'Day something','Day > something else') > I tried as.ordered, but I guess I am not using the > right function. > > How can I command the script to put the panels in the > original order given of the vector in a data frame? > > Thank you, > > Judith
You could strip the 'Day' part of the elements using gsub(), sort the numeric part and then paste() 'Day' back to the result: set.seed(1) day <- paste("Day", sample(-2:10)) > day [1] "Day 1" "Day 2" "Day 4" "Day 7" "Day -1" "Day 5" "Day 8" [8] "Day 10" "Day 3" "Day -2" "Day 9" "Day 0" "Day 6" day.tmp <- sort(as.numeric(gsub("[^0-9\\-]", "", day))) > day.tmp [1] -2 -1 0 1 2 3 4 5 6 7 8 9 10 day.levels <- paste("Day", day.tmp) > day.levels [1] "Day -2" "Day -1" "Day 0" "Day 1" "Day 2" "Day 3" "Day 4" [8] "Day 5" "Day 6" "Day 7" "Day 8" "Day 9" "Day 10" day.ord <- factor(day, levels = day.levels) # Note the order of the levels versus the order of the factor output > day.ord [1] Day 1 Day 2 Day 4 Day 7 Day -1 Day 5 Day 8 Day 10 Day 3 [10] Day -2 Day 9 Day 0 Day 6 13 Levels: Day -2 Day -1 Day 0 Day 1 Day 2 Day 3 Day 4 Day 5 ... Day 10 HTH, Marc Schwartz ______________________________________________ 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.