使用ggplot2将组均值线添加到barplot [英] Add group mean line to barplot with ggplot2

问题描述

我用geom_col()生成一个带有颜色分隔的两个类的barplot.然后，我尝试为每个班级添加一条平均线.

I generate a barplot with geom_col() with two classes separated by color. Then I try to add a mean line for each class.

这就是我想要得到的:

但是在下面的代码中，平均线是每个小节独立地放在组参数中的内容.

But with the code below the mean line is for each bar independently what I put to group argument.

以下是可重现的示例:

library(tidyverse)

df = data.frame(
  x = 1:10,
  y = runif(10),
  class = sample(c("a","b"),10, replace=T) %>% factor()
) %>% 
  mutate(x = factor(x, levels=x[order(class, -y)]))

ggplot(df, aes(x, y, fill=class)) +
geom_col() +
stat_summary(fun.y = mean, geom = "errorbar", 
             aes(ymax = ..y.., ymin = ..y.., group = class),
             width = 1, linetype = "solid")

请告诉我我在做什么错.还是任何其他方法(使用ggplot)来实现这一目标?

Please tell me what I'm doing wrong. Or any other way (with ggplot) to achieve this?

推荐答案

我使用@geom_errorbar将@bouncyball的解决方案与我的原始方法结合在一起.

I combined the solution from @bouncyball with my original approach using `geom_errorbar.

这是代码:

df.mean = df %>% 
  group_by(class) %>% 
  mutate(ymean = mean(y))

ggplot(df, aes(x, y, fill=class)) +
  geom_col() +
  geom_errorbar(data=df.mean, aes(x, ymax = ymean, ymin = ymean),
               size=0.5, linetype = "longdash", inherit.aes = F, width = 1)

唯一的问题是，这种方法不是生成单行，而是生成许多行对象，这些对象可以在编辑绘图时看到，例如在Adobe Illustrator中.但我可以忍受.

The only problem is that instead of single line this approach generate a lot of line objects which can be seen when editing the plot, for example, in Adobe Illustrator. But I can live with it.

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