title: R Shiny filter on data frame
body: <p>I need to apply a filter on data frame in my Shiny App.
  I am looking for some button (small one) that opens a multiselect list of values of a specific column. Something like Excel's table filter</p>
  
  <p><img src="https://i.stack.imgur.com/TPHj9.png" alt="Excel pivot table filter"></p>
  
  <p>As an example (from <a href="https://stackoverflow.com/questions/22646249/r-shiny-select-variable-based-on-checkboxgroupinput?rq=1">another topic</a>):</p>
  
  <pre><code>library(shiny)
  shiny::runApp(list(
    ui = fluidPage(
      checkboxGroupInput("specy", "Specy", choices = levels(iris$Species)),
      tableOutput("content")
    ),
    server = function(input, output, session) {
      output$content &lt;- renderTable({
        iris[iris$Species == input$specy, ]
      })
    }
  ))
  </code></pre>
  
  <p>Some idea from <a href="http://shiny.rstudio.com/gallery/widget-gallery.html" rel="nofollow noreferrer">the widget fallery</a>: use <code>checkboxGroupInput</code> that appears clicking on <code>actionButton</code></p>
  
  <p>All kind of suggestions are welcome. Thank's</p>