title: Convert the values in a column into row names in an existing data frame
body: <p>I would like to convert the values in a column of an existing data frame into row names. Is is possible to do this without exporting the data frame and then reimporting it with a <code>row.names = </code> call?</p>
  <p>For example I would like to convert:</p>
  <pre><code> &gt; samp 
       names Var.1 Var.2 Var.3
   1     A     1     5     0
   2     B     2     4     1
   3     C     3     3     2
   4     D     4     2     3
   5     E     5     1     4
  </code></pre>
  <p>Into:</p>
  <pre><code>&gt; samp.with.rownames 
       Var.1 Var.2 Var.3
  A     1     5     0
  B     2     4     1
  C     3     3     2
  D     4     2     3
  E     5     1     4
  </code></pre>