title: How to filter a DataFrame column of lists for those that contain a certain item
body: <p>If I want to filter a column of strings for those that contain a certain term I can do so like this:</p>
  
  <pre><code>df = pd.DataFrame({'col':['ab','ac','abc']})
  df[df['col'].str.contains('b')]
  </code></pre>
  
  <p>returns:</p>
  
  <pre><code>   col
  0   ab
  2  abc
  </code></pre>
  
  <p>How can I filter a column of lists for those that contain a certain item? For example, from</p>
  
  <pre><code>df = pd.DataFrame({'col':[['a','b'],['a','c'],['a','b','c']]})
  </code></pre>
  
  <p>how can I get all lists containing 'b'?</p>
  
  <pre><code>         col
  0     [a, b]
  2  [a, b, c]
  </code></pre>