combine lines in dataframe with same identifiant

I have this dataframe as a list:

l = [["a",1,2,"","",""],["a",1,2,3,"",""], ["a","",2,"3","4",""],["a",1,"","",4,5]]

I would like to combine all those lines to obtain this final line :

Ideally, I would flatten the list of lists to fill the blank value where needed. What would be the pythonest way to do that ?

>Solution :

Try:

import pandas as pd
import numpy as np

l = [["a",1,2,"","",""],["a",1,2,3,"",""], ["a","",2,"3","4",""],["a",1,"","",4,5]]

df = pd.DataFrame(l)



df.replace('',np.nan).ffill().tail(1)
df_out = df.replace('', np.nan).ffill().tail(1)
print(df_out)

Output:

   0    1    2  3  4    5
3  a  1.0  2.0  3  4  5.0