title: How to one-hot-encode from a pandas column containing a list?
body: <p>I would like to break down a pandas column consisting of a list of elements into as many columns as there are unique elements i.e. <code>one-hot-encode</code> them (with value <code>1</code> representing a given element existing in a row and <code>0</code> in the case of absence). </p>
  
  <p>For example, taking dataframe <strong>df</strong></p>
  
  <pre><code>Col1   Col2         Col3
   C      33     [Apple, Orange, Banana]
   A      2.5    [Apple, Grape]
   B      42     [Banana] 
  </code></pre>
  
  <p>I would like to convert this to:</p>
  
  <p><strong>df</strong> </p>
  
  <pre><code>Col1   Col2   Apple   Orange   Banana   Grape
   C      33     1        1        1       0
   A      2.5    1        0        0       1
   B      42     0        0        1       0
  </code></pre>
  
  <p>How can I use pandas/sklearn to achieve this?</p>