python - Joining two columns pandas - returning NA if any value is NA, however need to return real j-CodePudding

I have dataframe:

df = pd.DataFrame({'student_id': [71, 63, 23],
                   'student_name': [nan, 'Peter Andrews', 'Amy Powers'],
                   })

I am creating new column column which joins id name using

df['student_id_name'] = df['student_id'].astype(str) ' ' df['student_name']

Needed output:

{student_id_name : [71, 63 Peter Andrews, 23 Amy Powers]}

What I get:

{student_id_name : [nan, 63 Peter Andrews, 23 Amy Powers]}

May you help to get to expected outcome?

CodePudding user response：

Use Series.str.cat with na_rep parameter, last remove possible trailing spaces by Series.str.strip:

df['student_id_name'] = (df['student_id'].astype(str).str.cat(df['student_name'], 
                                                    sep=' ', na_rep='').str.strip())
print (df)
   student_id   student_name   student_id_name
0          71            NaN                71
1          63  Peter Andrews  63 Peter Andrews
2          23     Amy Powers     23 Amy Powers