title: Python: unexplode many boolean columns of Pandas DataFrame into one column?
body: <p>You have data in Pandas dataframe like</p>
  
  <pre><code>&gt;&gt; pd.DataFrame({'Cat' : [1,0,0], 'Fish' : [0,0,1], 'Parrot' : [0,1,0]})
  
  Cat | Fish | Parrot
  1   |  0   |   0
  0   |  0   |   1
  0   |  1   |   0
  </code></pre>
  
  <p>and you want </p>
  
  <pre><code>Animal
  Cat
  Parrot
  Fish
  </code></pre>
  
  <p><strong>how can you unexplode the boolean columns into the multivariate column with Animal heading?</strong></p>