如何使用ggplot2绘制美国地图，该地图根据是或否变量使用两种颜色填充特定的州

# 安装并加载必要的包
if (!require("maps")) install.packages("maps")
if (!require("ggplot2")) install.packages("ggplot2")

library(maps)
library(ggplot2)

# 获取美国地图数据
us_map <- map_data("state")

# 假设我们有一个数据框，包含州名和一个是或否的变量
data <- data.frame(
  state = c("California", "Texas", "New York", "Florida"),
  fill_color = c("yes", "no", "yes", "no")
)

# 合并地图数据和我们的数据
us_map <- merge(us_map, data, by = "region")

# 绘制地图
ggplot() +
  geom_polygon(data = us_map, aes(x = long, y = lat, group = group, fill = fill_color), color = "black") +
  scale_fill_manual(values = c("yes" = "blue", "no" = "red")) +
  labs(title = "US Map Colored by Yes/No Variable", fill = "Variable") +
  theme_minimal() +
  theme(panel.grid = element_blank())