Python Pandas Replace Values with NAN from Tuple

Question

Got the Following Dataframe:

   A    B
 Temp1  1
 Temp2  2
 NaN    NaN
 NaN    4

Since the A nad B are correlated, I am able to create new column where I have calculated the nan value of A and B and form a tuple:

 A      B       C
Temp1   1   (1,Temp1)
Temp2   2   (2, Temp2)
NaN    NaN  (3, Temp3)
NaN     4   (4, Temp4)

Now I have to drop the column C and fill the Nan value corrosponding to the Columns.

Answer 1

Use Series.fillna with select values in tuple by indexing with str, last remove C column:

#if values are not in tuples  
#df.C = df.C.str.strip('()').str.split(',').apply(tuple)

df.A = df.A.fillna(df.C.str[1]) 
df.B = df.B.fillna(df.C.str[0]) 
df = df.drop('C', axis=1)
print (df)
       A  B
0  Temp1  1
1  Temp2  2
2  Temp3  3
3  Temp4  4

Or create DataFrame from C with DataFrame.pop for use and remove column, set new columns names and pass to DataFrame.fillna:

#if values are not in tuples  
#df.C = df.C.str.strip('()').str.split(',').apply(tuple)

df[['A','B']] = df[['A','B']].fillna(pd.DataFrame(df.pop('C').tolist(), columns=['B','A']))
print (df)
       A  B
0  Temp1  1
1  Temp2  2
2  Temp3  3
3  Temp4  4