title: Convert month,day,year to month,year with python/pandas?
body: <p>I have this kind of list of strings with 9000 rows where each row is month/day/year:</p>
  
  <pre><code>10/30/2009
  12/19/2009
  4/13/2009
  8/18/2007
  7/17/2008
  6/16/2009
  1/14/2009
  12/18/2007
  9/14/2009
  2/13/2006
  3/25/2009
  2/23/2007
  </code></pre>
  
  <p>I want convert it and only have the list with month/year if is it possible as dateformat, like this:</p>
  
  <pre><code>10/2009
  12/2009
  4/2009
  8/2007
  7/2008
  6/2009
  1/2009
  12/2007
  9/2009
  2/2006
  3/2009
  2/2007
  </code></pre>