## Only run examples in interactive R sessions
if (interactive()) {
ui <- fluidPage(
  sliderInput("obs", "Number of observations", 0, 1000, 500),
  actionButton("goButton", "Go!"),
  plotOutput("distPlot")
)
server <- function(input, output) {
  output$distPlot <- renderPlot({
    # Take a dependency on input$goButton. This will run once initially,
    # because the value changes from NULL to 0.
    input$goButton
    # Use isolate() to avoid dependency on input$obs
    dist <- isolate(rnorm(input$obs))
    hist(dist)
  })
}
shinyApp(ui, server)
}
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