在从selectInput或sliderInput获取参数并单击ActionButton后，如何在R Shiny中执行函数？

selectInput(inputId = "param", label = "选择参数", choices = c("选项1", "选项2", "选项3"))

observeEvent(input$button, {
  myFunction(input$param)
})

myFunction <- function(param) {
  print(param)
}

# ui.R
library(shiny)

ui <- fluidPage(
  selectInput(inputId = "param", label = "选择参数", choices = c("选项1", "选项2", "选项3")),
  actionButton(inputId = "button", label = "执行函数")
)

# server.R
server <- function(input, output) {
  observeEvent(input$button, {
    myFunction(input$param)
  })
  
  myFunction <- function(param) {
    print(param)
  }
}

shinyApp(ui = ui, server = server)