title: How can I split a column of tuples in a Pandas dataframe?
body: <p>I have a Pandas dataframe (this is only a little piece)</p>
  <pre><code>&gt;&gt;&gt; d1
     y norm test  y norm train  len(y_train)  len(y_test)  \
  0    64.904368    116.151232          1645          549
  1    70.852681    112.639876          1645          549
  
                                      SVR RBF  \
  0   (35.652207342877873, 22.95533537448393)
  1  (39.563683797747622, 27.382483096332511)
  
                                          LCV  \
  0  (19.365430594452338, 13.880062435173587)
  1  (19.099614489458364, 14.018867136617146)
  
                                     RIDGE CV  \
  0  (4.2907610988480362, 12.416745648065584)
  1    (4.18864306788194, 12.980833914392477)
  
                                           RF  \
  0   (9.9484841581029428, 16.46902345373697)
  1  (10.139848213735391, 16.282141345406522)
  
                                             GB  \
  0  (0.012816232716538605, 15.950164822266007)
  1  (0.012814519804493328, 15.305745202851712)
  
                                               ET DATA
  0  (0.00034337162272515505, 16.284800366214057)  j2m
  1  (0.00024811554516431878, 15.556506191784194)  j2m
  &gt;&gt;&gt;
  </code></pre>
  <p>I want to split all the columns that contain tuples. For example, I want to replace the column <code>LCV</code> with the columns <code>LCV-a</code> and <code>LCV-b</code>.</p>
  <p>How can I do that?</p>