title: Using dates from an input file as min and max for slider input in shiny
body: <p>I have a shiny app in which I can load a file. I wan't to extract the min and max date range from  my file use these as input for a slider input.</p>
  
  <p>Here is what I have so far</p>
  
  <pre><code>ui &lt;- fluidPage(
  dateRangeInput(inputId = "date", label = "Input a date range", start=textOutput("datemin") , end = textOutput("datemax"),"%d-%m-%y"))
  )
  server = function(input, output){
  output$datemin &lt;- renderText({as.character(as.Date(paste("01",as.character.Date(min(dataset()$date)),sep="-"),"%d-%y-%m"))})
       output$datemax &lt;- renderText({as.character(as.Date(paste("01",as.character.Date(max(dataset()$date)),sep="-"),"%d-%y-%m"))})
  }
  </code></pre>
  
  <p>I know the outputs datemin and datemax are a bit tricky,  this is because the "date" column in the dataset is a string such as "13-05" for may 2013 (the dataset is a summarized version with monthly means for some values)</p>
  
  <p>Edit.</p>
  
  <p>I've tried 3 different outputs for my date in order to check the format, and I display them as textoutput as follows :</p>
  
  <p>UI</p>
  
  <pre><code>    textOutput("datemin1"),
      textOutput("datemin2"),
      textOutput("datemin3"),
  </code></pre>
  
  <p>Server</p>
  
  <pre><code> output$datemin1 &lt;- renderText({(as.character.Date(min(dataset()$date)))})
   output$datemin2 &lt;- renderText({as.character(as.Date(paste("01",as.character.Date(min(dataset()$datem)),sep="-"),"%d-%y-%m"))})
   output$datemin3 &lt;- reactive({as.Date(as.yearmon(min(dataset()$datem)))})
  </code></pre>
  
  <p>The outputs are the following :</p>
  
  <blockquote>
    <p>datemin1 : 14-01 <br> datemin2 : 2014-01-01 <br> datemin3 : 0014-01-01</p>
  </blockquote>
  
  <p>But still when I try to use an output as an input value for my slider as follows :</p>
  
  <pre><code>    sliderInput("slider1", "Date Range",
                  min = textOutput("datemin2"), max=textOutput("datemax2"),
                  value = textOutput("datemax2")
      ),
  </code></pre>
  
  <p>I get this error :
  ERROR: non-numeric argument to binary operator</p>
  
  <p>Thanks</p>