在-group内添加百分比标签，用于事前和事后的笼形数据ggplot barplot

library(ggplot2)

# 创建示例数据
data <- data.frame(
  group = c("A", "B", "C"),
  value = c(20, 30, 50)
)

# 计算百分比
data$percentage <- data$value / sum(data$value) * 100

# 创建柱状图
p <- ggplot(data, aes(x = group, y = value, fill = group)) +
  geom_bar(stat = "identity") +
  theme_minimal()

# 添加百分比标签
p <- p + geom_text(aes(label = paste0(percentage, "%")), vjust = -0.5)

# 显示图表
print(p)