title: Choosing a column in my dataframe to create line chart
body: <p>My data set has three columns.  One column for time, and two other columns for temperature measurements (Temp1, Temp2).  </p>
  
  <p>I want to be able to select Temp1 or Temp2 and graph the time series, but I am not sure how to do that in my server.R code.  What should go in my dygraph function call?</p>
  
  <pre><code># This is the server logic for a Shiny web application.
  # You can find out more about building applications with Shiny here:
  #
  # http://shiny.rstudio.com
  #
  
  library(shiny)
  library(dygraphs)
  
  shinyServer(function(input, output) {
  
    output$TempData &lt;- renderDygraph({
      data &lt;- switch(input$data,
                     "Temp 1" = Data1$Temp1,
                     "Temp 2" = Data1$Temp2),
      dygraph(data, main = "Temperature Rise Data") %&gt;%
  
       **I'm not sure what goes in here** 
  
    })
  
  })
  </code></pre>
  
  <p>and here is ui.R</p>
  
  <pre><code># This is the user-interface definition of a Shiny web application.
  # You can find out more about building applications with Shiny here:
  #
  # http://shiny.rstudio.com
  #
  
  library(shiny)
  library(dygraphs)
  
  shinyUI(fluidPage(
  
    # Application title
    titlePanel("Temperature Data"),
  
    # Sidebar with a slider input for number of bins
    sidebarLayout(
      sidebarPanel(
        selectInput("data", label = "Choose a Dataset",
                    choices = c("Temp 1", "Temp 1"),
                    selected = "Temp 1" ))
      ),
  
      # Show a plot of the generated distribution
      mainPanel(
        dygraphOutput("TempData")
      )
    )
  )
  </code></pre>