title: Arrange data frame reversed order
body: <p>I have a data frame which I want to order (not alphabetically) so I wrote this</p>
  
  <pre><code>z
    Grupos prueba$pendiente
  1     TR         12.48182
  2 TR2x45         39.87879
  3     UT         20.89545
  4 UT2x45         36.89015
  orden
  [1] "UT"     "TR"     "UT2x45" "TR2x45"
  z&lt;-arrange(z,orden)
  z
    Grupos prueba$pendiente
  1 TR2x45         39.87879
  2 UT2x45         36.89015
  3     TR         12.48182
  4     UT         20.89545
  </code></pre>
  
  <blockquote>
    <p>dput(z)
    structure(list(Grupos = structure(c(4L, 3L, 2L, 1L), .Label = c("UT", 
    "TR", "UT2x45", "TR2x45"), class = "factor"), <code>prueba$pendiente</code> = c(39.8787878787918, 
    36.8901515151553, 12.4818181818195, 20.8954545454566)), .Names = c("Grupos", 
    "prueba$pendiente"), row.names = c(NA, -4L), class = "data.frame")</p>
  </blockquote>
  
  <p>Arrange function is working, the only problem is I got the wrong order (reversed) I want UT to be my first value just like in <code>orden</code> vector.
  I'm sure it's a quite silly thing but I can't work it out.</p>
  
  <p>Thank you</p>