ggplot(mtcars, aes(x = mpg,
y = wt,
size = hp,
colour = as.factor(cyl))) +
geom_point() +
theme(legend.direction = "vertical",
legend.box = "horizontal",
legend.position = "bottom")
给我
我如何以一种方式生成图例,即圆柱标签保持垂直,而hp类别则水平排列?