Align order of multiindex dataframe with the order of another multiindex df, pandas

Question

I do have two multiindex dataframes, which contain the same multiindex levels. The only difference between them is the order in which the index levels are arranged.

Is there a way to reorder the levels of the multiindex from df1, so that they are the same as the ones from df2?

df1.index.names yields

FrozenList([u'Local code', u'Nature of holding', u'Issuer long name', u' Internal Issuer rating', u'holding type', u'Detailed Instrument'])

df2.index.names yields

FrozenList([u'Local code', u'Detailed Instrument', u'Nature of holding', u'Issuer long name', u'Internal Issuer rating', u'holding type'])

Is there a simple way to align the order of the index levels?

Answer 1

I think you need DataFrame.reorder_levels:

df1 = df1.reorder_levels(df2.index.names)

Sample:

df1 = pd.DataFrame({'A':[7,2,3],
                   'B':[5,5,6],
                   'C':[4,8,9],
                   'D':[0,3,5],
                   'E':[8,3,6],
                   'F':[9,4,3]}).set_index(['A','B', 'C'])

print (df1)
       D  E  F
A B C         
7 5 4  0  8  9
2 5 8  3  3  4
3 6 9  5  6  3

df2 = pd.DataFrame({'A':[1,2,3],
                   'B':[4,5,6],
                   'C':[7,8,9],
                   'D':[1,3,5],
                   'E':[5,3,6],
                   'F':[7,4,3]}).set_index(['C','A', 'B'])

print (df2)
       D  E  F
C A B         
7 1 4  1  5  7
8 2 5  3  3  4
9 3 6  5  6  3

df1 = df1.reorder_levels(df2.index.names)
print (df1)
       D  E  F
C A B         
4 7 5  0  8  9
8 2 5  3  3  4
9 3 6  5  6  3