title: splitting a column into multiple columns with specific name in pandas dataframe
body: <p>I have following dataframe:</p>
  
  <pre><code>pri    sec
  TOM    AB,CD,EF
  JACK   XY,YZ
  HARRY  FG
  NICK   KY,NY,SD,EF,FR
  </code></pre>
  
  <p>I need following output with column names as following(based on how many , separated fields exists in column 'sec'):</p>
  
  <pre><code>pri    sec             sec0  sec1  sec2  sec3 sec4
  TOM    AB,CD,EF        AB    CD    EF    NaN  NaN
  JACK   XY,YZ           XY    YZ    NaN   NaN  NaN
  HARRY  FG              FG    NaN   NaN   NaN  NaN
  NICK   KY,NY,SD,EF,FR  KY    NY    SD    EF   ER
  </code></pre>
  
  <p>Can I get any suggestions?</p>