title: Binary coding for multiple columns
body: <p>I have a Pandas table with coding like this:</p>
  
  <pre><code>id var1 var2 var3
  1   1    3    4
  2   2    5
  3   1    2 
  </code></pre>
  
  <p>An would like to have it converted to binary like this</p>
  
  <pre><code>id x1 x2 x3 x4 x5
  1  1  0  1  1  0
  2  0  1  0  0  1
  3  1  1  0  0  0
  </code></pre>
  
  <p>So effectively mapping each variable's position.</p>