如何在分组条形图上制作水平线，同时显示与每个组和图例对应的平均值？

Question

我的代码：

library(tidyverse)
library(lubridate)
library(ggplot2)

category <- c("apple", "apple", "apple","orange", "orange","orange")
mean_diameter_cm <- c(5.2,6.4,6.0, 9.2,8.6,8.1)
location <- c("Farm A","Farm B", "Farm C","Farm A","Farm B", "Farm C")
myfruit_data <- data.frame(category, mean_diameter_cm, location)

myfruit_data %>% 
    group_by(category, location) %>% 
    summarise(average_diameter = mean(mean_diameter_cm)) %>% 
    ggplot(aes(x=location, y=average_diameter, fill=category)) +
    geom_col(position = "dodge")

我的条形图

我尝试手动计算每组的平均值，添加水平线和颜色，如下所示：

geom_line() +
geom_hline(yintercept = mean_diameter_cm,
          color = c("green","red"))

这种方法的问题是我不知道如何手动添加相应的图例并显示平均值，即使我这样做了，对于一个不太复杂的任务来说似乎有点太复杂了，所以我我认为必须有一些我不知道的功能来完成更简单的方法，这就是我在这里问的原因。提前谢谢你。

Answer 1

也许这有帮助

library(dplyr)
library(ggplot2)
myfruit_data %>% 
    group_by(category) %>%
    mutate(avg = mean(mean_diameter_cm)) %>% 
    ungroup %>% 
    mutate(colr = case_when(category == "apple" ~ "green",
          TRUE ~ "red")) %>% 
    ggplot(aes(x=location, y=mean_diameter_cm, fill=category)) +
    geom_col(position = "dodge") + 
        geom_line() + 
        geom_hline(aes(yintercept = avg, colour = colr)) + 
        guides(color = FALSE)

-输出

Answer 2

我有点不确定你想要什么，但也许是这个？

ggplot(myfruit_data, aes(x=location, y=mean_diameter_cm, fill = category)) +
  geom_col(position = "dodge") +   geom_hline(data = myfruit_data %>%                              
                                                group_by(category) %>%                      
                                                summarise_at(vars(mean_diameter_cm),           
                                                             list(Mean = mean)), aes(yintercept = Mean, color = category))

如何在分组条形图上制作水平线，同时显示与每个组和图例对应的平均值？

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