如何在R中仅绘制从面板数据中选中的国家？

install.packages("ggplot2")
install.packages("dplyr")
install.packages("tidyr")

library(ggplot2)
library(dplyr)
library(tidyr)

panel_data <- read.csv("panel_data.csv")

selected_countries <- c("China", "United States")
selected_data <- panel_data %>% filter(Country %in% selected_countries)

summarized_data <- selected_data %>%
  group_by(Country, Time) %>%
  summarise(mean_variable = mean(Variable))

ggplot(summarized_data, aes(x = Time, y = mean_variable, color = Country)) +
  geom_line() +
  labs(title = "Selected Countries Panel Data",
       x = "Time",
       y = "Mean Variable") +
  theme_minimal()