[R Shiny]：如何按x轴上的时间范围过滤，同时在R Shiny应用程序中y轴上有两个不同的变量

ui <- fluidPage(
  titlePanel("R Shiny App"),
  sidebarLayout(
    sidebarPanel(
      dateRangeInput("date_range", "选择时间范围：", start = NULL, end = NULL)
    ),
    mainPanel(
      plotOutput("plot")
    )
  )
)

server <- function(input, output) {
  # 读取和处理数据集
  data <- read.csv("data.csv")
  
  # 根据用户选择的时间范围过滤数据
  filtered_data <- reactive({
    start_date <- input$date_range[1]
    end_date <- input$date_range[2]
    subset(data, date >= start_date & date <= end_date)
  })
  
  # 绘制图形
  output$plot <- renderPlot({
    plot(filtered_data()$date, filtered_data()$variable1, type = "l", col = "blue", xlab = "时间", ylab = "变量1")
    lines(filtered_data()$date, filtered_data()$variable2, col = "red")
    legend("topright", legend = c("变量1", "变量2"), col = c("blue", "red"), lty = 1)
  })
}

shinyApp(ui, server)