我怎样才能 plot 条形图中特征的平均值？

Question

I have followed barplot example:

library(ggplot2)
df <- read.csv("https://raw.githubusercontent.com/plotly/datasets/master/violin_data.csv")

g <- ggplot(df, mapping = aes(forcats::fct_infreq(sex), fill = as.factor(size))) +
  geom_bar(colour = "white") + coord_flip() + 
  geom_text(aes(label = paste0("n=", ..count..)), stat='count', 
            position = position_stack(vjust = 0.5))
g

Which gives me:

What I want is the mean of the size from the Female and the Male:

Answer 1

To get the mean of values by size, you could create a mean column first,

df %>% 
  group_by(sex) %>% 
  mutate(mean = mean(size)) %>% 
  ungroup() %>% 
  ggplot(aes(fct_infreq(sex))) +
  geom_bar(aes(fill = as.factor(size)), colour = "white") + 
  geom_text(aes(label = sprintf("mean = %.2f",mean)), stat="count", position = position_stack(vjust = 0.5)) +
  coord_flip()

---

Previous answer: When you set the aesthetics with aes inside the ggplot function, it will affect all future geom_ commands, but here you should not use the same aes for geom_bar and geom_text :

ggplot(df, aes(fct_infreq(sex))) +
  geom_bar(aes(fill = as.factor(size)), colour = "white") + 
  geom_text(aes(label = paste0("mean=", ..count..)), stat="count", position = position_stack(vjust = 0.5)) +
  coord_flip()