旋转箱线图例（R，ggplot2）

Question

我正在使用以下代码。

 library(ggplot2)
 mtcars$carb <- as.factor(mtcars$carb)
 mtcars$am <- as.factor(mtcars$am)
 mtcars <- mtcars[!(mtcars$carb==6 | mtcars$carb==8),]
 ggplot(mtcars) + 
    geom_boxplot(aes(x = carb, y = mpg, fill = am), 
                 position = position_dodge(0.9)) +
 guides(fill = guide_legend(direction = "horizontal"))

结果是：

我想旋转图例以获得所需的结果：

有人可以帮忙吗？谢谢。

Answer 1

好的，我根据@LFischer的建议弄清楚了。也许有一种更简单的方法，但是经过反复试验，这为我做到了：

 library(ggplot2)
 mtcars$carb <- as.factor(mtcars$carb)
 mtcars$am <- as.factor(mtcars$am)
 mtcars <- mtcars[!(mtcars$carb==6 | mtcars$carb==8),]
 ggplot(mtcars) + 
    geom_boxplot(aes(x = carb, y = mpg, fill = am), 
                 position = position_dodge(0.9)) +
 guides(fill = guide_legend(reverse = TRUE, direction = "vertical", label.position = "top", label.theme = element_text(angle = 90, vjust = 0.5), title.position = "bottom", title.theme = element_text(angle = 90)))

Answer 2

您可以将其放在顶部

library(ggplot2)
 mtcars$carb <- as.factor(mtcars$carb)
 mtcars$am <- as.factor(mtcars$am)
 mtcars <- mtcars[!(mtcars$carb==6 | mtcars$carb==8),]
 ggplot(mtcars) + 
    geom_boxplot(aes(x = carb, y = mpg, fill = am), 
                 position = position_dodge(0.9)) +
theme(legend.position = "top")

或者您可以使其垂直

library(ggplot2)
mtcars$carb <- as.factor(mtcars$carb)
mtcars$am <- as.factor(mtcars$am)
mtcars <- mtcars[!(mtcars$carb==6 | mtcars$carb==8),]
ggplot(mtcars) + 
  geom_boxplot(aes(x = carb, y = mpg, fill = am), 
               position = position_dodge(0.9)) +
  theme(legend.direction = "vertical")

希望有帮助