On Mar 27, 2008, at 1:47 PM, Agustin Lobo wrote: > Thanks, it was a matter of reshaping the data matrix as I usually have > it, ie: > datos <- > data.frame(x=abs(round(rnorm(100,10,5))),y=abs(round(rnorm > (100,2,1))),f=factor(round(runif(100,1,3)))) > > to become: > > datos2 <- > data.frame(V1=c(datos[,1],datos[,2]),"VAR"=c(rep("x",100),rep("y", > 100)),f=factor(c(datos[,3],datos[,3]))) > > and then > require(lattice) > barchart(V1~VAR|f,data=datos2) > > I get horizontal lines in the bars that I do not understand, though.
In order to understand the lines , you should ask: What does the height of each bar correspond to? As you have set things up, the "x" bar in panel "1" should somehow correspond to the all values: datos2$V1[datos2$VAR=="x" & datos2$f==1] [1] 15 13 14 1 18 14 8 12 7 19 10 1 5 14 7 9 14 7 5 10 6 12 10 11 11 7 15 [28] 9 4 12 17 10 4 5 So you should ask yourself, how you expect R to produce a single column, which in some sense corresponds to just one single number, its height, from these different values. My guess is that you want R to show you just the mean on each group. For me this is not a barplot, but anyway. What happens in the barplot you have now, I think, is this that R will start by constructing a bar with height 15, then put on it a bar of height 13, then on it a bar of height 14 and so on. So the lines you see account for the boxes that survive: > x<-datos2$V1[datos2$VAR=="x" & datos2$f==1] > unique(cummax(rev(x))) [1] 5 10 17 19 I would recommend using boxplots instead of "barplots only showing the means". If you really want barplots of the means, I think you can do the following: datos3 <- with(datos2, aggregate(x=V1, by=list(VAR=VAR,f=f), mean)) barchart(x~VAR|f, datos3) Another option would be ggplot2 I think, but I'll let someone knowledgeable with that package speak up. > Agus > Haris Skiadas Department of Mathematics and Computer Science Hanover College ______________________________________________ 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.