fill one dataframe with values ​from another

Question

I have this Dataframe, which is null values that haven't been populated right.

      Unidad  Precio Combustible  Año_del_vehiculo  Caballos  \
49          1    1000    Gasolina            1998.0      50.0   
63          1     800    Gasolina            1998.0      50.0   
88          1     600    Gasolina            1999.0      54.0   
107         1    3100      Diésel            2008.0      54.0   
244         1    2000      Diésel            1995.0      60.0   
...       ...     ...         ...               ...       ...   
46609       1   47795    Gasolina            2016.0     420.0   
46770       1   26900    Gasolina            2011.0     450.0   
46936       1   19900    Gasolina            2007.0     510.0   
46941       1   24500    Gasolina            2006.0     514.0   
47128       1   79600    Gasolina            2017.0     612.0   

      Comunidad_autonoma         Marca_y_Modelo Año_Venta       Año_Comunidad  \
49        Islas Baleares             CITROEN AX      2020  2020Islas Baleares   
63        Islas Baleares             SEAT Arosa      2021  2021Islas Baleares   
88        Islas Baleares          FIAT Seicento      2020  2020Islas Baleares   
107             La Rioja            TOYOTA Aygo      2020        2020La Rioja   
244               Aragón            PEUGEOT 205      2019          2019Aragón   
...                  ...                    ...       ...                 ...   
46609           La Rioja        PORSCHE Cayenne      2020        2020La Rioja   
46770           Cataluña               AUDI RS5      2020        2020Cataluña   
46936     Islas Baleares  MERCEDES-BENZ Clase M      2020  2020Islas Baleares   
46941           La Rioja  MERCEDES-BENZ Clase E      2020        2020La Rioja   
47128     Islas Baleares  MERCEDES-BENZ Clase E      2021  2021Islas Baleares   

           Fecha  Año  Super_95  Diesel Comunidad Salario en euros anuales  
49    2020-12-01  NaN       NaN     NaN       NaN                      NaN  
63    2021-01-01  NaN       NaN     NaN       NaN                      NaN  
88    2020-12-01  NaN       NaN     NaN       NaN                      NaN  
107   2020-12-01  NaN       NaN     NaN       NaN                      NaN  
244   2019-03-01  NaN       NaN     NaN       NaN                      NaN  
...          ...  ...       ...     ...       ...                      ...  
46609 2020-12-01  NaN       NaN     NaN       NaN                      NaN  
46770 2020-07-01  NaN       NaN     NaN       NaN                      NaN  
46936 2020-10-01  NaN       NaN     NaN       NaN                      NaN  
46941 2020-11-01  NaN       NaN     NaN       NaN                      NaN  
47128 2021-01-01  NaN       NaN     NaN       NaN                      NaN 

I need to fill the gasoline, diesel and salary tables with the values of the following:

     Año  Super_95    Diesel Comunidad Año_Comunidad      Fecha  \
0    2020  1.321750  1.246000   Navarra   2020Navarra 2020-01-01   
1    2020  1.301000  1.207250   Navarra   2020Navarra 2020-02-01   
2    2020  1.224800  1.126200   Navarra   2020Navarra 2020-03-01   
3    2020  1.106667  1.020000   Navarra   2020Navarra 2020-04-01   
4    2020  1.078750  0.986250   Navarra   2020Navarra 2020-05-01   
..    ...       ...       ...       ...           ...        ...   
386  2021  1.416600  1.265000  La rioja  2021La rioja 2021-08-01   
387  2021  1.431000  1.277000  La rioja  2021La rioja 2021-09-01   
388  2021  1.474000  1.344000  La rioja  2021La rioja 2021-10-01   
389  2021  1.510200  1.382000  La rioja  2021La rioja 2021-11-01   
390  2021  1.481333  1.348667  La rioja  2021La rioja 2021-12-01   

    Salario en euros anuales  
0                  27.995,96  
1                  27.995,96  
2                  27.995,96  
3                  27.995,96  
4                  27.995,96  
..                       ...  
386                21.535,29  
387                21.535,29  
388                21.535,29  
389                21.535,29  
390                21.535,29  

It would fill the columns of the first with the second when the year_community table matches. for example in the nan where 2020Islas Baleares appears in the same row. fill in with the value of the price of gasoline from the other table where 2020Islas Baleares appears in the same row. In the case that it is 2020aragon, it would be with 2020 aragon and so on. I had thought of something like this:

analisis['Super_95'].fillna(analisis2['Super_95'].apply(lambda x: x if x=='2020Islas Baleares' else np.nan), inplace=True)

the second dataframe is the result of doing a merge, and those null values have not worked

Answer 1

df1.merge(df2, on='Año_Comunidad')

As a result you'll have one DataFrame where columns with same names will have a suffix _x for first DataFrame and _y for the second one.

Now to fill in the blanks you can do this for each column:

df1.loc[df1["Año_x"].isnull(),'Año_x'] = df1["Año_y"]

If a row in Año is empty, it will be filled with data from second table that we merged earlier.
You can do it in a cycle for all the columns:

cols = ['Año',  'Super_95',  'Diesel', 'Comunidad', 'Salario en euros anuales']
for col in cols:
    df1.loc[df1[col+"_x"].isnull(), col+'_x'] = df1[col+'_y']

And finally you can drop the merged columns:

for col in cols:
    df1 = df1.drop(col+'_y', axis=1)