title: How to extract the hour of this kind of timestamp?
body: <p>This is how my timestamp looks like  </p>
  
  <pre><code>date1 = timestamp[1]
  
  date1
  [1] 07.01.2016 11:52:35
  3455 Levels: 01.02.2016 00:11:52 01.02.2016 00:23:35 01.000:30:21    31.01.2016 23:16:18
  </code></pre>
  
  <p>When I try to extract the hour, I get an invalid 'trim' argument. Thank you !</p>
  
  <pre><code> format(date1, "%I")
  
   Error in format.default(structure(as.character(x), names = names(x), dim = dim(x),  : 
  </code></pre>
  
  <p>invalid 'trim' argument</p>
  
  <p>How can I extract single components like the hour from this timestamp.</p>