Try this X = rbind(y1, y2) colnames(X) = as.character(x)
barplot( X, density=c(35,40), col=c("red","blue"), beside=FALSE) barplot( X, density=c(35,40), col=c("red","blue"), beside=TRUE) Alternatively, barplot( y1, ylim = c(0, max(y1,y2)), col="blue", beside=FALSE) par(new=TRUE) barplot( y2, ylim = c(0, max(y1,y2)), col="red", beside=FALSE, names.arg=as.character(x)) Mama ----- Mama Attiglah, PhD Advanced Research Center Quantitative Research Analyst State Street Bank +44(0)20 7698 6290 (Direct Line) +44 (0)207 004 2968 (Direct Fax) Please visit our Web site at www.ssga.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gustaf Granath Sent: 29 January 2008 16:15 To: r-help@r-project.org Subject: [R] How to get two y-axises in a bar plot? Hi, I have measured two response variables (y1, y2) at each treatment level (x = 0, 1.5 or 3). Now I would like to show the y1 and y2 against x in a bar plot. However, y1 and y2 differ in scale so I need two y-axises, one on the left side and one on the right side (and I dont want to standardize my responses). This is fairly easy if you want to show points,lines etc, but gets more complicated with bars.Although these kind of bar graphs are quite common, I have found very limited information about how to do them in R. I have been struggling with the barplot() command. My problem is that the bars for y1 and y2 end up at the same place (blocking each other) and not beside each other when I use par(new=TRUE). Is there a way to separate them so y1 and y2 are placed beside each other at each x level, or is this easier to do this with lattice?? I would also like to add error bars but I guess that should not be a problem. For code and data, see below. Cheers, Gustaf Granath, phd student My code so far: #Creating data c(6.34,13.38,17.87)->y1 c(0.85,1.88,2.33)->y2 c(0,1.5,3)->x cbind(y1,y2,x)->mydata data.frame(mydata)->mydata with(mydata, tapply(y1,x,mean))->mean.y1 with(mydata, tapply(y2,x,mean))->mean.y2 #Barplot par(mar=c(5,4,4,4)+0,1) barplot(mean.y1,density=1,las=1) par(new=T) barplot(mean.y2,density=3,angle=3,axes=F) axis(4,las=1) ______________________________________________ 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. ______________________________________________ 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.