title: Comparing lists with order
body: <p>I wish to compare lists and output the similar matches that following each other in the same order.</p>
  <pre><code>list1 = ['a','b', 'b', 'c']
  list2 = ['b', 'a', 'a', 'c']
  
  # With the intersection() command, the output is the matching strings regardless of the order of the strings:
  set(list1).intersection(set(list2))
  {'a', 'b', 'c'}
  
  # I wish to output only the strings that are following each other in the two lists. Here the two answers could be :
  {'a', 'c'}
  # or
  {'b', 'c'}
  </code></pre>
  <p>Would you know any tricks to do it?</p>