Swap level-one from index with column level (Pandas Multiindex Dataframe)

Question

I have a multiindexed pandas.Dataframe which is something like this:

          BAZ    PAL
Foo  Bar          
124   1    A     B
      2    C     D
134   1    E           


        

Answer 1

You need to unstack your existing index level Foo, stack your desired column 'Coo', and then rearrange the index levels. After swapping your index levels, you probably want to sort it. As a final touch, you may want to drop the column name of all the values (val).

df = (pd.DataFrame({'Foo': [124, 124, 134, 134] * 2, 
                    'Bar': [1, 2, 1, 2] * 2, 
                    'Coo': ['BAZ'] * 4 + ['PAL'] * 4, 
                    'val': list('ACEGBDFH')})
      .set_index(['Foo', 'Bar', 'Coo'])
      .unstack('Coo'))

>>> df
        val    
Coo     BAZ PAL
Foo Bar        
124 1     A   B
    2     C   D
134 1     E   F
    2     G   H

df = df.unstack('Foo').stack('Coo')
df.index = df.index.swaplevel(0, 1)

>>> df
        val    
Foo     124 134
Coo Bar        
BAZ 1     A   E
PAL 1     B   F
BAZ 2     C   G
PAL 2     D   H

df.sort_index(inplace=True)

>>> df
        val    
Foo     124 134
Coo Bar        
BAZ 1     A   E
    2     C   G
PAL 1     B   F
    2     D   H

df.columns = df.columns.droplevel()

>>> df
Foo     124 134
Coo Bar        
BAZ 1     A   E
    2     C   G
PAL 1     B   F
    2     D   H