title: How to make the filter function on dates in sparkR
body: <p>'u' is a DataFrame containing ID = 1, 2, 3 .. and time= "2010-01-01", "2012-04-06", ..
  ID and time have type string. I convert type of time' to 'Date'</p>
  
  <pre><code>u$time &lt;- cast(u[[2]], "Date")
  </code></pre>
  
  <p>I now want the first time in u. </p>
  
  <pre><code>first &lt;- first(u$time)
  </code></pre>
  
  <p>I now make a new time by adding 150 days to the first time</p>
  
  <pre><code>cluster&lt;- first+150
  </code></pre>
  
  <p>I now want to make a subset. I want to have a new 'u' where the times are from the  first 150 days.</p>
  
  <pre><code>ucluster &lt;- filter(u, u$time &lt; cluster)
  </code></pre>
  
  <p>but this can't run in sparkR. I get this message "returnstatus==0 is not TRUE".</p>