You want to assign your call to boxplot as an object that contains the plot information
set.seed(1) b <- matrix(rgamma(100,(1:4)/2,.5),nc=4) (bxp <- boxplot(b)) Now you can use the info in bxp for placement, e.g.: text(1:length(bxp$names),bxp$stats[3,],round(bxp$stats[3,],2),pos=3) By the way, the "line in the middle" is the median, not the mean. points(apply(b,2,median),col=2,pch='x') points(colMeans(b),col=2) HTH On Thu, Mar 15, 2012 at 6:04 AM, Cleland <tom.alb...@tribalgroup.com> wrote: > Hello there, > > I was wondering if anyone might be able to help me as I'm pretty new to R. > I'm trying to create a boxplot from a data table returned from an sproc. I > have the following code, which generates the plot as I'd like it: > > library("RODBC"); > conn <- odbcConnect("datawarehouse"); # connect to datawarehouse > results <- sqlQuery(conn, "call sproc)"); > ylab <- 'Percentage (%)' > main = 'Productivity Overview - 6 mnths'; > par(mai=c(1.5,1,1,0.2), las = 2, xpd=TRUE, cex.axis=0.8, cex.lab=0.8); > col = c('forestgreen', 'forestgreen', 'forestgreen', 'chocolate', > 'chocolate', 'chocolate', 'goldenrod', 'goldenrod', 'goldenrod'); > b <- results[,4:12] > boxplot(b, col=col, ylab=ylab, main=main, boxwex=0.4); > > What i'd like to do is add the mean value, demarcated by the black line in > the middle of each box, to the plot. The only way I've managed to add values > previously is by specifying their exact value and location on the plot e.g. > > text(1.4,2.139,format("Mean (2.14)",digits=2), cex=1); > > I need these values to be dynamic in the sense that they will be different > each time the graph is generated (based on the parameters passed through the > sproc) and will need to be in a different position each time (i.e. in-line > with the mean for each box). > > I'm uncertain about a. whether this is possible in R and b. if it is > possible, how best I could achieve it. > > If anyone has any advice it would be gratefully received. > > Thanks in advance. > > Tom > > -- > View this message in context: > http://r.789695.n4.nabble.com/Adding-mean-values-to-boxplots-tp4474700p4474700.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. ______________________________________________ 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.