Shiny example: Diamonds Explorer

app.R

library(shiny)
library(ggplot2)

dataset <- diamonds

ui <- pageWithSidebar(
  
  headerPanel("Diamonds Explorer"),
  
  sidebarPanel(
    
    sliderInput('sampleSize', 'Sample Size', 
                min = 1, max = nrow(dataset),
                value = min(1000, nrow(dataset)), 
                step = 500, round = 0),
    
    selectInput('x', 'X', names(dataset)),
    selectInput('y', 'Y', names(dataset), names(dataset)[[2]]),
    selectInput('color', 'Color', c('None', names(dataset))),
    
    checkboxInput('jitter', 'Jitter'),
    checkboxInput('smooth', 'Smooth'),
    
    selectInput('facet_row', 'Facet Row', c(None='.', names(dataset))),
    selectInput('facet_col', 'Facet Column', c(None='.', names(dataset)))
  ),
  
  mainPanel(
    plotOutput('plot')
  )
)

server <- function(input, output) {
  
  dataset <- reactive({
    diamonds[sample(nrow(diamonds), input$sampleSize), ]
  })
  
  output$plot <- renderPlot({
    
    p <- ggplot(dataset(), aes_string(x = input$x, y = input$y)) + 
      geom_point()
    
    if (input$color != 'None')
      p <- p + aes_string(color=input$color)
    
    facets <- paste(input$facet_row, '~', input$facet_col)
    if (facets != '. ~ .')
      p <- p + facet_grid(facets)
    
    if (input$jitter)
      p <- p + geom_jitter()
    if (input$smooth)
      p <- p + geom_smooth()
    
    print(p)
    
  }, height = 700)
  
}

shinyApp(ui, server)