在ggplot2中旋转图例

Question

我希望将ggplot2图例旋转90°

从

qplot(mpg, wt, data=mtcars, colour=cyl)

生产

Answer 1

就像是：

p <- qplot(mpg, wt, data=mtcars, colour=cyl)
p + scale_colour_continuous(guide = guide_legend(direction = "horizontal", title.position = "top",
                             label.position="bottom", label.hjust = 0.5, label.vjust = 0.5,
                             label.theme = element_text(angle = 90))) + 
      theme(legend.position = c(0.5, 0.9))

参考：ggplot 文档