title: Pandas dataframe: how do I split one row into multiple rows by multi-value column?
body: <p>I have a dataframe that appears as follows:</p>
  
  <pre><code>   issue_key date     pkey          component              case_count
  0  1060  2018-03-08  PROJ  console,configuration,management    8   
  1  1464  2018-04-24  PROJ2 protocol                            1   
  2  611   2017-03-31  PROJ  None                                2
  3  2057  2018-10-30  PROJ  ha, console                         0
  </code></pre>
  
  <p>I need to split the rows with multiple values in the component column into one row per component.</p>
  
  <p>When done, the dataframe should appear as follows:</p>
  
  <pre><code>   issue_key date     pkey          component              case_count
  0  1060  2018-03-08  PROJ  console                           8
  1  1060  2018-03-08  PROJ  configuration                     8
  2  1060  2018-03-08  PROJ  management                        8   
  3  1464  2018-04-24  PROJ2 protocol                          1   
  4  611   2017-03-31  PROJ  None                              2
  5  2057  2018-10-30  PROJ  ha                                0
  6  2057  2018-10-30  PROJ  console                           0
  </code></pre>
  
  <p>Any suggestions on how best to do this?</p>