GGPLOT2: Distance of discrete values of from each end of x-axis

Question

I have been working with the code below. Everything seems to work okay, except that the discrete values on the x-axis are far from each end of the graph. I\'ve tried several

Answer 1

Try it again, but convert vicryl.long$pre_post to a continuous numeric variable rather than a factor and it will plot to the edges, rather than center (as it should) as a categorical variable.

vicryl.long$pre_post <- as.numeric(as.character(vicryl.long$pre_post))