Concatenate 2 dataframes based on conditions-CodePudding

I have 2 dataframes, df_products_cp, like this one:

product_id	version	country
1111	2	CO
1111	2	BR
1111	2	MX
2222	2	CO
3333	2	CO
3333	2	MX
4444	2	CO
4444	2	BR
4444	2	MX

and df_products_ec like this one:

product_id	version	country
1111	3	CO
1111	3	MX
2222	3	CO
4444	3	CO
4444	3	BR

How can I concatenate both so that I only get a single dataframe like this one, when the product_id/country combination is found in both dataframes?

product_id	version	country
1111	2	CO
1111	3	CO
1111	2	MX
1111	3	MX
2222	2	CO
2222	3	CO
4444	2	CO
4444	3	CO
4444	2	BR
4444	3	BR

CodePudding user response：

Let us do merge then wide_to_long

out = pd.wide_to_long(df1.merge(df2,on=['product_id','country']),
                      'version',
                      ['product_id','country'],
                      j = 'drop',
                      suffix = '\w ').reset_index().drop(['drop'],axis = 1)
Out[275]: 
   product_id country  version
0        1111      CO        2
1        1111      CO        3
2        1111      MX        2
3        1111      MX        3
4        2222      CO        2
5        2222      CO        3
6        4444      CO        2
7        4444      CO        3
8        4444      BR        2
9        4444      BR        3