I have two dataframes,

df1                       df2
country                   country
US                        AR
US                        AD
CA                        AO
CN                        AU
AR                        US

How do I group by them by combining the country list to a set the compare the difference between two dataframes?

My expected output will be like,

country code   df1_country_count   df2_country_count
AR                   1                    1
AD                   0                    1
AO                   0                    1
AU                   0                    1
US                   2                    1 
CA                   1                    0
CN                   1                    0

>Solution :

(df1.value_counts().to_frame('df1_country_count')
 .join(df2.value_counts().to_frame('df2_country_count'), how='outer')
 .fillna(0).astype('int').rename_axis('country code'))

result:

               df1_country_count    df2_country_count
country code        
AD             0                    1
AO             0                    1
AR             1                    1
AU             0                    1
CA             1                    0
CN             1                    0
US             2                    1