title: How to shuffle columns independently
body: <p>How to shuffle/permute/randomize with R values independently in all columns in big data frame and remain order of columns. Example:</p>
  
  <pre><code>&gt; M
    head1 head2 head3
  1     1     a     A
  2     2     b     B
  3     3     c     C
  4     4     d     D
  
  &gt; M
    head1 head2 head3
  1     2     b     D
  2     4     a     A
  3     1     d     B
  4     3     c     C
  </code></pre>