Filling Missing Values Pandas Dataframe By Specific Value

I have a dataset and I want to fill the missing data in the column 'value' with bfill with adding a string to it. Here is to code that I have: import pandas as pd import numpy as

Solution 1:

IIUC

s=df.value.bfill()
s.loc[df.value.isnull()]=s.astype(int).astype(str)+'5D'
s
Out[771]: 
0      1
1    25D
2    25D
3      2
4      3
5      1
6      3
7    35D
8      3
Name: value, dtype: object