title: order vector or POSIXct not working
body: <p>I have a vector of POSIXct elements and I want to sort them descending but it is not working. Here is a toy model. I cannot simply reverse the order of the indicies because the dates are not sorted in any order. </p>
  
  <p>input:</p>
  
  <pre><code>    dateTime&lt;- as.POSIXct(c("2014-10-27 12:31:01 PDT","2014-10-27 14:59:01 PDT","2014-10-27 05:45:01 PDT"))
      class(dateTime)
  sort(as.POSIXlt(dateTime),descending = TRUE)
  sort(as.POSIXlt(dateTime), descending= FALSE)
  </code></pre>
  
  <p>output:</p>
  
  <blockquote>
    <p>sort(as.POSIXlt(dateTime),descending = TRUE)
    [1] "2014-10-27 05:45:01 PDT" "2014-10-27 12:31:01 PDT" "2014-10-27 14:59:01 PDT"</p>
    
    <p>sort(as.POSIXlt(dateTime), descending= FALSE)
    [1] "2014-10-27 05:45:01 PDT" "2014-10-27 12:31:01 PDT" "2014-10-27 14:59:01 PDT"</p>
  </blockquote>
  
  <p>You can see that descending does not seem to work. </p>
  
  <p>any help?</p>