shinyApp6a.R

# https://github.com/rstudio-education/shiny.rstudio.com-tutorial/tree/master/part-3-code

rm(list=ls())

library(shiny)

ui <- navbarPage(title = "Random generator",
                 tabPanel(title = "Normal data",
                          plotOutput("norm"),
                          actionButton("renorm", "Resample")
                 ),
                 tabPanel(title = "Uniform data",
                          plotOutput("unif"),
                          actionButton("reunif", "Resample")
                 ),
                 tabPanel(title = "Chi Squared data",
                          plotOutput("chisq"),
                          actionButton("rechisq", "Resample")
                 )
                 
)

server <- function(input, output) {
  
  rv <- reactiveValues(
    norm = rnorm(500), 
    unif = runif(500),
    chisq = rchisq(500, 2))
  
  observeEvent(input$renorm, { rv$norm <- rnorm(500) })
  observeEvent(input$reunif, { rv$unif <- runif(500) })
  observeEvent(input$rechisq, { rv$chisq <- rchisq(500, 2) })
  
  output$norm <- renderPlot({
    hist(rv$norm, breaks = 30, col = "grey", border = "white",
         main = "500 random draws from a standard normal distribution")
  })
  output$unif <- renderPlot({
    hist(rv$unif, breaks = 30, col = "grey", border = "white",
         main = "500 random draws from a standard uniform distribution")
  })
  output$chisq <- renderPlot({
    hist(rv$chisq, breaks = 30, col = "grey", border = "white",
         main = "500 random draws from a Chi Square distribution with two degree of freedom")
  })
}

shinyApp(ui, server)