我的第一个R闪亮，我如何结合selectinput和renderplot(ggplot)？

library(shiny)
library(ggplot2)

# 定义UI
ui <- fluidPage(
  titlePanel("Select Input and Render Plot Example"),
  sidebarLayout(
    sidebarPanel(
      selectInput("dataset", "Choose a dataset:",
                  choices = c("mtcars", "iris", "pressure")),
      submitButton("Submit")
    ),
    mainPanel(
      plotOutput("plot")
    )
  )
)

# 定义服务器逻辑
server <- function(input, output) {
  output$plot <- renderPlot({
    # 根据选择的dataset生成绘图
    dataset <- switch(input$dataset,
                      "mtcars" = mtcars,
                      "iris" = iris,
                      "pressure" = pressure)
    ggplot(dataset, aes(x = mpg, y = hp)) +
      geom_point() +
      labs(title = paste("Dataset:", input$dataset))
    })
  })
}

# 运行Shiny应用程序
shinyApp(ui = ui, server = server)