R – I like it, but it's so difficult… same goes for ggplot2!

It took me an hour to figure this out: I had a plot, arranged as 2 panels by using facet_grid(. ~ group). The factor “group” has 2 levels, so that went fine. But then I wanted to add different text to the 2 panels using the test geom, and it always repeated all text on both panels. The solution was hidden in some advice I managed to google:  the text geom needs its own dataframe, yes, but the important thing is that in that dataframe there must also be a factor named “group” with 2 levels. So I created the dataframe like so:

 dd = data.frame(group=c(“control”, “patient”),       lbl=c(paste0(“p=”, format(pValueCtrl, digits=2)),paste0(“p=”, format(pValuePtnt, digits=2)))), 

and in the ggplot-sequence I added

 geom_text(data=dd, aes(x=20,y=1,label=lbl))

resulting in the attached figure, which my coauthors found beautiful (as do I :). [I obfuscated the ordinate because the paper is not even submitted yet.]