ggplot2：通过在某些标签上添加星号来自定义x轴

Question

Using the built in R dataset ToothGrowth

ggplot(ToothGrowth, aes(x=dose,y=len,colour=supp)) +
  geom_point()

Is there a way to add an asterisk to some of the x-axis labels? For instance 1.0 and 2.0?

Answer 1

How about:

 library(ggplot2)
  ggplot(ToothGrowth, aes(x=dose,y=len,colour=supp)) +
    geom_point() + scale_x_continuous(breaks = seq(0.5, 2, 0.5),
                                      ,labels = c("0.5","1*","1.5", "2*"))