ggplot箱线图颜色与代码设置不符，寻求解决方法

你的代码中指定了十六进制颜色但输出显示默认的红、蓝、绿，核心原因是：ggplot将你映射到fill/color美学的box_color、point_color等列，当作分类变量处理，自动分配了默认的离散调色板，而非直接使用你指定的颜色值。

修复方案 #

只需在绘图代码中添加scale_fill_identity()和scale_color_identity()，告诉ggplot直接使用映射变量的数值（即你定义的十六进制颜色码）作为颜色：

修改后的完整绘图代码：

# Create the plot
p1 <- filtered_cAMP_fen %>%
  filter(Assay_type == 'cAMP', Cell_Line %in% Plot_Line, exclusion == 'no', Treatment == treatments_for_plot) %>%
  ggplot(aes(x = as.factor(race_gen), y = cAMP_normed_meoh)) +
  geom_boxplot(aes(fill = box_color)) +
  geom_point(aes(fill = point_color, color = point_border),
             position = position_jitterdodge(jitter.width = 0.2, dodge.width = 0.75),
             shape = 21, size = 6) +
  # 关键：添加这两行，让ggplot直接使用指定的颜色值
  scale_fill_identity() +
  scale_color_identity() +
  theme(legend.position = "none",
        panel.background = element_rect(fill = "#FFFFFF"),
        panel.grid = element_blank(),
        axis.ticks.x = element_blank(),
        axis.text.x = element_text(size = 14),
        axis.text.y = element_text(size = 14),
        axis.title.y = element_text(size = 14),
        axis.line = element_line(color = "black"))

print(p1)

可选优化：简化颜色赋值代码 #

你可以用更简洁的逻辑替代重复的case_when条件，让代码更易维护：

filtered_cAMP_fen <- filtered_cAMP_fen %>%
  mutate(
    point_color = ifelse(race_gen %in% c("White_fem", "White_male"), "#000000", "#FFFFFF"),
    point_border = ifelse(race_gen %in% c("White_fem", "White_male", "Asian_fem", "Asian_male"), "#000000", "#FFFFFF"),
    box_color = case_when(
      race_gen %in% c("White_fem", "White_male") ~ "#FFFFFF",
      race_gen %in% c("Black_fem", "Black_male") ~ "#000000",
      race_gen %in% c("Asian_fem", "Asian_male") ~ "#8B0000"
    )
  )

内容的提问来源于stack exchange，提问作者Detlef Obal