使用R中的ggplot2在分类散点图中添加水平线

install.packages("ggplot2")

library(ggplot2)

data <- data.frame(x = c("A", "B", "C", "A", "B", "C"),
                   y = c(1, 2, 3, 4, 5, 6),
                   hline = c(2.5, 4.5, 5.5, 3.5, 2.5, 4.5))

ggplot(data, aes(x = x, y = y)) +
  geom_point() +
  geom_hline(aes(yintercept = hline))

ggplot(data, aes(x = x, y = y, color = x, shape = x)) +
  geom_point() +
  geom_hline(aes(yintercept = hline)) +
  labs(title = "分类散点图",
       x = "分类变量",
       y = "连续变量",
       color = "分类变量",
       shape = "分类变量") +
  theme_minimal()