title: Contingency table in Python
body: <p>Given two lists of equal length, how can I construct a <a href="https://en.wikipedia.org/wiki/Contingency_table#Example" rel="nofollow">contingency table</a> in a truly pythonic way?
  I know about confusion_matrix from <a href="http://scikit-learn.org/stable/" rel="nofollow">skit-learn</a>, but are there 'manual' and effective ways to do that?</p>