inst/examples-shiny/01_hello/app.R

In shiny: Web Application Framework for R

library(shiny)
library(bslib)

# Define UI for app that draws a histogram ----
ui <- page_sidebar(

  # App title ----
  title = "Hello Shiny!",

  # Sidebar panel for inputs ----
  sidebar = sidebar(

    # Input: Slider for the number of bins ----
    sliderInput(
      inputId = "bins",
      label = "Number of bins:",
      min = 1,
      max = 50,
      value = 30
    )
  ),

  # Output: Histogram ----
  plotOutput(outputId = "distPlot")
)

# Define server logic required to draw a histogram ----
server <- function(input, output) {

  # Histogram of the Old Faithful Geyser Data ----
  # with requested number of bins
  # This expression that generates a histogram is wrapped in a call
  # to renderPlot to indicate that:
  #
  # 1. It is "reactive" and therefore should be automatically
  #    re-executed when inputs (input$bins) change
  # 2. Its output type is a plot
  output$distPlot <- renderPlot({
    x <- faithful$waiting
    bins <- seq(min(x), max(x), length.out = input$bins + 1)

    hist(
      x,
      breaks = bins,
      col = "#75AADB",
      border = "white",
      xlab = "Waiting time to next eruption (in mins)",
      main = "Histogram of waiting times"
    )
  })
}

# Create Shiny app ----
shinyApp(ui = ui, server = server)