如何使用ggplot分组并显示前X个类别？

install.packages("ggplot2")

# 导入数据
df <- data.frame(x = 1:10, y = rnorm(10), group = rep(c("A", "B", "C", "D"), each = 5))

# 使用 ggplot2 进行分组绘制
library(ggplot2)
ggplot(df, aes(x = x, y = y, group = group, color = group)) +
  geom_line() +
  geom_smooth(method = "loess") +
  labs(title = "Showing top 3 categories", x = "x", y = "y") +
  scale_color_manual(values = c("A" = "#0066FF", "B" = "#EE9900", "C" = "#CC33CC", "D" = "#000000")) +
  theme_bw() +
  theme(panel.border = element_blank(), panel.grid = element_blank(),
        strip.text = element_text(size = 14, face = "bold"),
        axis.text.x = element_text(size = 12), axis.text.y = element_text(size = 12),
        axis.title.x = element_blank(), axis.title.y = element_blank())