I have a scatter plot in R (with ggplot2). The data has a numeric column (let's call it "bin") which can contain various integer values or null.
I would like to colour the points with non-null bin values differently from the others. I do not want to one colour per value of bin, that would be too noisy. Just simply, say, red for those with a non-null bin and black for the others.
qplot has a colour attribute but I don't know how to express a condition like colour = bin != null ? "red" : "black"
Thank you.