title: Python data Manipulation: Splitting Data from one column to make more rows in the same dataframe
body: <p>So my input is:</p>
  
  <pre><code>   Col1         Col2      Col3 Col4
  0   123  abc,def,ghi  Country1  XXX
  1   456      pqr,stu  Country2   XX
  2   789          xyz  Country2   YY
  </code></pre>
  
  <p>I want my output as :</p>
  
  <pre><code>   Col1      Col2    Col3   Col4
  0    abc     123  Country1    XXX
  1    def     123  Country1    XXX
  2    ghi     123  Country1    XXX
  3    pqr     456  Country2     XX
  4    stu     456  Country2     XX
  5    xyz     789  Country2     YY
  </code></pre>
  
  <p>What would be the most pythonic way to do this pls? Thanks vm!</p>