by() will sort on the levels of `class', so I think what you need to do is ensure that `class' has its levels sorted numerically. Try
df$class <- factor(as.numeric(as.character(df$class))) to do that. Then to sort the df by numerical class you could use df <- df[sort.list(unclass(df$class)), ] It might be easier just to make class a number for some purposes at least (just omit the factor() above). On Thu, 15 Jan 2004, Scott Norton wrote: > > I have a dataframe such that when I enter the dataframe name at the R prompt > and see the data, the order of the data is correct (ie. what I want - > ordered numerically by the factor, class). The table is akin to the > following: > > df: (dataframe = df) > uniqueID class age > a 1 32 > b 1 21 > c 1 13 > d 1 11 > e 3 15 > f 3 16 > g 3 31 > h 3 25 > i 4 23 > j 4 32 > k 4 31 > l 7 11 > m 7 6 > n 7 20 > o 10 19 > p 10 25 > q 10 42 > . > . > . > > > uniqueID and class are factors. Yesterday I think I managed to figure out > how to arrange the column "class" in "numerical" order (when it lists) even > though it's a "character" factor. (although feel free to pipe in an answer > on that too - since I was trying a lot of different things!) > > Now, when I execute the following command: > > barplot(by(df[,"age"],df$class,FUN=function(x) quantile(x,0.95))) > > the x-labels or "class" of each bar is in *character* order, not *numerical > order. > > Is there a way to rearrage this so that each bar label (categorical x-label) > is in numerical order? > > Thanks in advance!!! > Best, > Scott > > > > > > > [[alternative HTML version deleted]] > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > > -- Brian D. Ripley, [EMAIL PROTECTED] 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 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html