How can I suppress the vertical gridlines in a ggplot2 plot while retaining the x-axis labels?

Question

This is a follow-on from this question, in which I was trying to suppress the vertical gridlines.

The solution, as provided by learnr, was to add scale_x_continuous(brea

Answer 1

The answers above will not work in ggplot2 version 0.9.2.1 and above. Fortunately, there is now an easier way to do this, as described in response to a different question: https://stackoverflow.com/a/8992102/800044.