r - ggplot2: Have shorter tick marks for tick marks without labels

Question

I have a plot using ggplot2 in which I'd like many ticks along the x-axis, yet only some of the ticks will have tick labels associated with them. However, I'd like the tick marks for those that have labels to be longer than those that don't.

Answer 1

In base R, you can suppress the x-axis with the initial plot call (with xaxt='n'), and then use tcl to control tick length (see ?par) with two axis(1, ...) calls.

plot(1:10, xaxt='n', ylab='', las=1)
axis(1, at=1:10, tcl=-0.8)
axis(1, at=seq(0, 11, 0.2), labels=NA)