使用ggplot2绘制热图中的级别

library(ggplot2)

# 准备数据集
df <- data.frame(
  x = c("A", "A", "A", "B", "B", "B", "C", "C", "C"),
  y = c("X", "Y", "Z", "X", "Y", "Z", "X", "Y", "Z"),
  value = c(1, 2, 3, 4, 5, 6, 7, 8, 9)
)

# 创建绘图对象
p <- ggplot()

# 添加热图矩形区域
p <- p + geom_tile(data = df, aes(x = x, y = y, fill = value))

# 设置颜色映射
p <- p + scale_fill_gradient(low = "blue", high = "red")

# 设置标签
p <- p + labs(x = "X轴标签", y = "Y轴标签", fill = "数值")

# 调整绘图外观
p <- p + theme(
  panel.background = element_rect(fill = "white"),
  panel.grid = element_blank(),
  axis.text = element_text(size = 12),
  legend.position = "right"
)

# 打印热图
print(p)