ggplot2：通過在某些標簽上添加星號來自定義x軸

Question

使用內置的R數據集ToothGrowth

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

是否可以在某些X軸標簽上添加星號？ 例如1.0和2.0？

Answer 1

怎么樣：

 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*"))