如何在存在多个组的单个直方图中 plot 多条平均线？

Question

I am plotting a distribution of two variables on a single histogram. I am interested in highlighting each distribution's mean value on that graph through a doted line or something similar (but hopefully something that matches the color present already in the aes section of the code).
How would I do that?

This is my code so far.

hist_plot <- ggplot(data, aes(x= value, fill= type,  color = type)) +
geom_histogram(position="identity", alpha=0.2) +
labs( x = "Value", y = "Count", fill = "Type", title = "Title") +
guides(color = FALSE)

Also, is there any way to show the count of n for each type on this graph?

Answer 1

i've made some reproducible code that might help you with your problem.

library(tidyverse)

# Generate some random data
df <-  data.frame(value = c(runif(50, 0.5, 1), runif(50, 1, 1.5)), 
                  type = c(rep("type1", 50), rep("type2", 50)))

# Calculate means from df
stats <- df %>% group_by(type) %>% summarise(mean = mean(value),
                                             n = n())

# Make the ggplot
ggplot(df, aes(x= value, fill= type,  color = type)) +
  geom_histogram(position="identity", alpha=0.2) +
  labs(x = "Value", y = "Count", fill = "Type", title = "Title") +
  guides(color = FALSE) +
  geom_vline(data = stats, aes(xintercept = mean, color = type), size = 2) +
  geom_text(data = stats, aes(x = mean, y = max(df$value), label = n), 
            size = 10, 
            color = "black")

If things go as intended, you'll end up something akin to the following plot.

histogram with means