在R个分组的ggplot2中包含总平均值

install.packages("ggplot2")

library(ggplot2)

df <- data.frame(group = c("Group A", "Group B", "Group C"),
                 value = c(10, 15, 12))

p <- ggplot(data = df, aes(x = group, y = value))

p <- p + geom_bar(stat = "summary", fun = "mean")

total_mean <- mean(df$value)
p <- p + geom_hline(yintercept = total_mean, linetype = "dashed", color = "red")

p <- p + labs(title = "Average Value by Group",
              x = "Group",
              y = "Value")

print(p)