title: Conversion of dates in the dataframe column into MM/DD/YYYY
body: <p>I have 4 dataframes named <code>df1</code>,<code>df2</code>,<code>df3</code>,<code>df4</code> with one column <code>Date</code>. The column consist of dates with different format. <code>df1</code> has date column of type int64, <code>df2</code> has date column of type object, <code>df3</code> has date column has type object, <code>df4</code> has date column of type object. Below are the dataframe and its data.</p>
  
  <pre><code>df1:
            Date
  0     20160301
  1     20160301
  2     20160301
  3     20160301
  
  df2: 
        Date
  0   01/03/2016
  1   01/03/2016
  2   01/03/2016
  
  df3:
        Date
  0   31-Mar-16
  1   31-Mar-16
  2   31-Mar-16
  
  df4:
        Date
  0  25/02/2016
  1  25/02/2016
  2  25/02/2016
  </code></pre>
  
  <p>I want to convert these dates in the form as <code>mm/dd/yyyy</code> of type <code>date</code>. Can anyone help me on this? </p>