If the number of panels in the last row is different to the rows above, the x-axis labels are missing in a facet plot with ggplot2. How can I add these?
For example:
d <- ggplot(diamonds, aes(carat, price, colour=color))
d + geom_point() + facet_wrap(~ clarity, ncol=5)
gives:
where the carat labels are missing for columns 4 and 5.