在ggplot中将平均线添加到双因子箱图中

Question

我想为6组中的每一组添加一条平均线，但是ggplot会添加一组平均线。情节目前如下所示：box plot

ggplot(test, aes(Factor1, YVar)) + geom_boxplot(aes(colour=Factor2)) + 
  labs(x="Factor 1", y="Y Var") +
  guides(color=guide_legend("Factor 2"))+
  stat_summary(fun.y=mean, geom="errorbar", aes(ymax=..y..,ymin=..y..), 
               width=0.75, linetype="dashed", size=1, color="black")

以上是代码的样子（不包括颜色等）。

有人可以帮忙吗？为这个简单的问题提前道歉。干杯！

Answer 1

只需在Factor2的电话中添加group作为stat_summary美学 - 这是一个更可重复的示例：

library(ggplot2)

# Original boxplot
ggplot(mtcars, aes(factor(cyl), mpg)) +
  geom_boxplot(aes(color = factor(am)))

# With dashed mean line
ggplot(mtcars, aes(factor(cyl), mpg)) +
  geom_boxplot(aes(color = factor(am))) +
  stat_summary(fun.y = mean, geom = "errorbar", 
               aes(ymax = ..y.., ymin = ..y.., group = factor(am)),
               width = 0.75, linetype = "dashed")

# Use position = position_dodge()
ggplot(mtcars, aes(factor(cyl), mpg)) +
  geom_boxplot(aes(color = factor(am))) +
  stat_summary(fun.y = mean, geom = "errorbar", 
               aes(ymax = ..y.., ymin = ..y.., group = factor(am)),
               width = 0.75, linetype = "dashed", position = position_dodge())

由reprex package（v0.2.0）创建于2018-04-17。