R Shiny Stuff

server.R

library("shiny")
library("datasets")
library("ggplot2")

#from here http://web.stanford.edu/~cengel/cgi-bin/anthrospace/building-my-first-shiny-application-with-ggplot
# We tweak the "am" field to have nicer factor labels. Since this doesn't
# rely on any user inputs we can do this once at startup and then use the
# value throughout the lifetime of the application
mpgData <- mtcars
mpgData$am <- factor(mpgData$am, labels = c("Automatic", "Manual"))

# Define server logic required to plot various variables against mpg
shinyServer(function(input, output) {

# Compute the forumla text in a reactive expression since it is
# shared by the output$caption and output$mpgPlot expressions
formulaText <- reactive({
paste("mpg ~", input$variable)
})

# Return the formula text for printing as a caption
output$caption <- renderText({
formulaText()
})

# Generate a plot of the requested variable against mpg and only
# include outliers if requested
# ggplot version
output$mpgPlot <- renderPlot({

# check for the input variable
if (input$variable == "am") {
# am
mpgData <- data.frame(mpg = mtcars$mpg, var = factor(mtcars[[input$variable]], labels = c("Automatic", "Manual")))
}
else {
# cyl and gear
mpgData <- data.frame(mpg = mtcars$mpg, var = factor(mtcars[[input$variable]]))
}

p <- ggplot(mpgData, aes(var, mpg)) +
geom_boxplot(outlier.size = ifelse(input$outliers, 2, NA)) +
xlab(input$variable)
print(p)

})
})

ui.R

library(shiny)

# Define UI for miles per gallon application
shinyUI(pageWithSidebar(

  # Application title
  headerPanel("Miles Per Gallon"),

  # Sidebar with controls to select the variable to plot against mpg
  # and to specify whether outliers should be included
  sidebarPanel(
    selectInput("variable", "Variable:",
                list("Cylinders" = "cyl", 
                     "Transmission" = "am", 
                     "Gears" = "gear")),

    checkboxInput("outliers", "Show outliers", FALSE)
  ),

  # Show the caption and plot of the requested variable against mpg
  mainPanel(
    h3(textOutput("caption")),

    plotOutput("mpgPlot")
  )
))