如何使用ggplot2在条形图顶部添加另一数据集的文本标注

完整可运行代码 #

# 加载所需包
library(ggplot2)
library(dplyr)

# 原始数据定义
school <- c("A","A","A","B","B","B","C","C","C")
satisify <- c("yes","yes","no","no","no","yes","no","no","yes")
evaluate <- as.data.frame(cbind(c("A","B","C"),c("good","terrible","terrible"),c("open","close","close")))
colnames(evaluate) <- c("school","evaluate","decision")
data <- as.data.frame(cbind(school, satisify))

# 统计每个学校各满意度的占比
data_summary <- data %>%
  group_by(school, satisify) %>%
  summarise(count = n(), .groups = "drop_last") %>%
  mutate(prop = count / sum(count)) %>%
  ungroup()

# 构造标注数据集
label_data <- data_summary %>%
  group_by(school) %>%
  # 取学校最高条形高度上浮10%作为标注位置，避免重叠
  summarise(max_y = max(prop) * 1.1, .groups = "drop") %>%
  left_join(evaluate, by = "school") %>%
  # 用换行符拼接两个标注字段，实现上下两行显示
  mutate(full_label = paste(evaluate, decision, sep = "\n"))

# 绘图
ggplot(data_summary, aes(x = school, y = prop, fill = satisify)) +
  geom_col(position = position_dodge(0.9), width = 0.8) +
  geom_text(
    data = label_data,
    aes(x = school, y = max_y, label = full_label),
    inherit.aes = FALSE,
    size = 3.5
  )

关键调整说明 #

• 提前汇总条形占比数据，比在geom_bar中使用..prop..实时统计的逻辑更可控，也更容易匹配标注位置
• 单独构造标注专用数据集，通过\n拼接两个标注内容，自动实现上下两行的显示效果
• geom_text层设置inherit.aes = FALSE，避免继承全局的fill等映射规则导致报错
• 标注高度预留10%的空隙，避免和条形顶部重叠

内容的提问来源于stack exchange，提问作者Mizzle