如何在ggplot柱状图中添加趋势线并高亮GoDigit？

背景 #

已通过ggplot生成保险公司分年度保费的分组柱状图，需完成两个优化：

1. 为每个保险公司添加跨年度的趋势连线
2. 高亮显示"GoDigit"对应的柱状条目

现有代码：

Recreated_figure_DHRP %>% 
  ggplot(aes(x = Insurers, y =`INR BN`,fill = FY,group=FY)) +
  geom_bar(stat = "identity", position = position_dodge(), alpha = 0.75,)+
  theme(axis.text.x = element_text(angle = 60, hjust = 1)) +
  theme(legend.position="top") +
  ylim(0,400)+
  geom_text(aes(label = `INR BN`), fontface = "bold", vjust = 1.5,
            position = position_dodge(.9), size = 2.25)

解决方案 #

1. 添加跨年度趋势线 #

趋势线需要按**保险公司（Insurers）**分组，连接同一公司不同年度的数值点。在现有代码中添加geom_line和geom_point，注意重新指定group参数：

# 新增趋势线和数据点
geom_line(aes(group = Insurers), color = "darkslategray", size = 1, position = position_dodge(.9)) +
geom_point(aes(group = Insurers), color = "darkslategray", size = 2, position = position_dodge(.9))

• position = position_dodge(.9) 保证线和点与柱状图的分组位置对齐
• 调整color和size参数可匹配目标图的样式

2. 高亮GoDigit条目 #

可以通过给GoDigit的柱状图添加红色边框实现高亮，在geom_bar之后新增一个针对GoDigit子集的图层：

# 高亮GoDigit的柱子
geom_bar(data = subset(Recreated_figure_DHRP, Insurers == "GoDigit"), 
         stat = "identity", position = position_dodge(), 
         color = "red", size = 1.2, fill = NA)

• fill = NA 保留原有填充色，只显示边框
• 若需要改变填充色，可替换fill为指定颜色（如fill = "#ffcccc"）

完整代码 #

Recreated_figure_DHRP %>% 
  ggplot(aes(x = Insurers, y =`INR BN`,fill = FY,group=FY)) +
  # 基础柱状图
  geom_bar(stat = "identity", position = position_dodge(), alpha = 0.75)+
  # 高亮GoDigit
  geom_bar(data = subset(Recreated_figure_DHRP, Insurers == "GoDigit"), 
           stat = "identity", position = position_dodge(), 
           color = "red", size = 1.2, fill = NA)+
  # 趋势线和点
  geom_line(aes(group = Insurers), color = "darkslategray", size = 1, position = position_dodge(.9))+
  geom_point(aes(group = Insurers), color = "darkslategray", size = 2, position = position_dodge(.9))+
  # 原有样式设置
  theme(axis.text.x = element_text(angle = 60, hjust = 1)) +
  theme(legend.position="top") +
  ylim(0,400)+
  geom_text(aes(label = `INR BN`), fontface = "bold", vjust = 1.5,
            position = position_dodge(.9), size = 2.25)

内容的提问来源于stack exchange，提问作者Jimi13 ABC