How to plot ticks and numbers of y and x axes in a ggplot graph?

Question

I'm plotting a graph using ggplot. Here is the exemple with the ggplot package:

df <- data.frame(
  gp = factor(rep(letters[1:3], each = 10)),
  y = rnorm(30)
)
ds <- plyr::ddply(df, "gp", plyr::summarise, mean = mean(y), sd = sd(y))

ggplot(df, aes(gp, y)) +
  geom_point() +
  geom_point(data = ds, aes(y = mean), colour = 'red', size = 3) +
  theme(    axis.text.y = element_text(hjust = 3),
            axis.text.x = element_text(vjust = 5),
            axis.ticks.length = unit(-0.25,
                                     "cm"), # length of the axis ticks

  )

Here is the output:

As you can see, the ticks are inside but the numbers for the y axis are terribly aligned and the ones on the X axis are overlapping the ticks.

So in the end I'd want the ticks inside the graph and the axis labels (the numbers) inside the ggplot graph. I've heard that we should use the margin tool, but I'm not sure how to specify margins inside the graph.

Edit: You can see how when using the margin function, the numbers are not aligned properly...

Answer 1

Maybe specifying margin within element_text using the margin function is what you are looking for?

ggplot(df, aes(gp, y)) +
  geom_point() +
  geom_point(data = ds, aes(y = mean), colour = 'red', size = 3) +
  theme(    axis.text.y = element_text(margin = margin(0,-.5,0,.5, unit = 'cm')),
            axis.text.x = element_text(vjust = 5, margin = margin(-0.5,0,0.5,0, unit = 'cm')),
            axis.ticks.length = unit(-0.25,
                                     "cm") , # length of the axis ticks

  ) + ylim(c(min(df$y)-.5,max(df$y)))