title: Simple way to extract date from text in Pandas
body: <p>The excerpt from data:</p>
  
  <p>Givent the following example of pandas dataframe:</p>
  
  <pre><code>df = 
         index              date
          7838      2012 January
          7790      2012 January
          7853    2015 September
          7889        2016 March
          7928      2015 October
          7847      1999 January
          7884      2006 January
          7826      1992 January
  </code></pre>
  
  <p>Is there a simple (and pythonic) way to convert free text into a standard date time variable? Something like:</p>
  
  <pre><code>df = 
             index              date
              7838        2012-01-01
              7790        2012-01-01
              7853        2015-09-01
              7889        2016-03-01
              7928        2015-10-01
              7847        1999-01-01
              7884        2006-01-01
              7826        1992-01-01
  </code></pre>