Combining two MultiIndex dataframes

Question

I have two MultiIndex dataframes that I'd like to combine into one.

I've tried to concat the two dataframes with pd.concat([df1, df2], axis=1, keys=('value_1', 'value_1')).swaplevel(1, 0, axis=1) but the resulting dataframe comes out like this:

product     A           B            A               B
            v1          v2          v1          v2      
date                                                                                    
2018-01-31  -0.123519   -0.113372    0.215493   0.025099    
2018-02-28  -0.072106   -0.115016   -0.128000   0.006867    
2018-03-31  0.008197    0.025000     0.396766   -0.028422   

Where I was expecting an output like this

product     A                        B               
            v1          v2          v1          v2      
date                                                                                    
2018-01-31  -0.123519   -0.113372    0.215493   0.025099    
2018-02-28  -0.072106   -0.115016   -0.128000   0.006867    
2018-03-31  0.008197    0.025000     0.396766   -0.028422   

Answer 1

Try adding this on:

df.sortlevel(0, axis=1, inplace=True)