title: Change number format in renderDataTable
body: <p>How do I define number format for datatable in Shiny? I would like to display 2 decimal digits only for some columns, but do not understand where it should be defined in my application. In <code>server.R</code> or <code>ui.R</code>? In <code>server.R</code>, this what I have in <code>renderDataTable</code>:</p>
  
  <pre><code>  output$woeTable &lt;- renderDataTable({
      input$tryTree
      input$threshold
      # The following returns data frame with numeric columns
      get(input$dfDescr)[['variables']][[input$columns]][['woe']]
      },
      options=list(
        paging = FALSE,
        searching = FALSE)
    ) 
  </code></pre>
  
  <p>How do I format 2nd and 3rd column to display only two decimal digits?</p>