This question is an attempt to generalise the solution provided for the this question: Pandas: add a column to a multiindex column dataframe I need to produce a column for each column index. The solution provided by spencerlyon2 works when we want to add a single column: df['bar', 'three'] = [0, 1, 2] However I would like to generalise this operation for every first level column index. Source DF: In [1]: df Out[2]: first bar baz second one two one two A -1.089798 2.053026 0.470218 1.440740 B 0.488875 0.428836 1.413451 -0.683677 C -0.243064 -0.069446 -0.911166 0.478370 Target DF below, requires that the three column is the addition of the one and two columns of its respective index. In [1]: df Out[2]: first bar baz second one two three one two three A -1.089798 2.053026 0.963228 1.440740 -2.317647 -0.876907 B 0.488875 0.428836 0.917711 -0.683677 0.345873 -0.337804 C -0.243064 -0.069446 -0.312510 0.478370 0.266761 0.745131 Continue reading...
