title: Python pandas give comma separated values new column
body: <p>Hello I have a csv file and it currently has 2 columns with 1000> rows.  I want each comma seperated value to be a new column from the one column that it is in.</p>
  
  <p>Here is an example of my csv:</p>
  
  <pre><code>print df4
  
   keys                                                env
  0         FIT-2990                                          3000.0010
  1         FIT-2918                                          3000.0004
  2         FIT-2854                               2110.0070, 2110.0071
  3    UXSCIENCE-640                                          1808.0001
  4         FIT-2814                    1135.0017, 1135.0018, 1135.0019
  5         FIT-2766                               1908.0043, 1908.0044
  6         FIT-2760  1901.0012, 1903.0045, 1906.0020, 1922.0032, 19...
  7         FIT-2725                                          0147.0001
  8         FIT-2706                               1903.0045, 1922.0032
  9         FIT-2554                               1802.0024, 1805.0028
  10        FIT-2383                                             , 1910
  11        FIT-2339                                          2113.0021
  12   UXSCIENCE-438                    4000.0237, 4000.0238, 4000.0339
  13        FIT-2201                    2023.0013, 2016.0013, 2019.0013
  </code></pre>
  
  <p>I want to split ex : 2110,0070 | 2110.0071 into separate columns for the entire csv.  </p>
  
  <p>What I got so far..</p>
  
  <pre><code>df5 = df4.join(df4.apply(lambda x: Series(x.split(', '))))
  print df5
  </code></pre>