如何在shiny中创建简单的线性预测模型？

install.packages("shiny")
install.packages("caret")

library(shiny)
library(caret)

ui <- fluidPage(
  titlePanel("简单线性预测模型"),
  
  sidebarLayout(
    sidebarPanel(
      numericInput("x", "输入X值:", value = 0),
      actionButton("predict", "预测")
    ),
    mainPanel(
      textOutput("prediction")
    )
  )
)

server <- function(input, output) {
  
  # 创建一个简单的线性模型
  model <- reactive({
    train(mpg ~ wt, data = mtcars, method = "lm")
  })
  
  # 当点击预测按钮时进行预测
  output$prediction <- renderText({
    if (input$predict > 0) {
      predict(model(), newdata = data.frame(wt = input$x))
    }
  })
}

shinyApp(ui = ui, server = server)