ggplot2 Diamonds Explorer
In flexdashboard: R Markdown Format for Flexible Dashboards

# load data in 'global' chunk so it can be shared by all users of the dashboard
library(ggplot2)
library(mgcv)
dataset <- diamonds

Inputs {.sidebar}

sliderInput('sampleSize', 'Sample Size', min=1, max=nrow(dataset),
            value=min(1000, nrow(dataset)), step=500, round=0)

checkboxInput('jitter', 'Jitter', value = TRUE)
checkboxInput('smooth', 'Smooth', value = TRUE)

selectInput('x', 'X', names(dataset))
selectInput('y', 'Y', names(dataset), names(dataset)[[2]])
selectInput('color', 'Color', c('None', names(dataset)))

selectInput('facet_row', 'Facet Row',
            c(None='.', names(diamonds[sapply(diamonds, is.factor)])))
selectInput('facet_col', 'Facet Column',
            c(None='.', names(diamonds[sapply(diamonds, is.factor)])))

Outputs

Diamonds

dataset <- reactive({
  diamonds[sample(nrow(diamonds), input$sampleSize),]
})

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)
})