How can I replace a nan value in an "object" column?-CodePudding

How can I replace a nan value in a column which is an 'object', contains other str and ensure it goes into the main df and not just the slice.

I have tried this

covid_19_df.Country_code.fillna('OT')

but it is still empty

 D    Country_code    Country   
 1.   OM              Oman  
 2.   OM              Oman  
 3.                   Other
 4.                   Other 
 5.                   Other

I want it to look like this

 D    Country_code    Country   
 1.   OM              Oman  
 2.   OM              Oman  
 3.   OT              Other
 4.   OT              Other 
 5.   OT              Other

CodePudding user response：

fillna does not replace inplace by default, you have to save the operation:

covid_19_df.Country_code = covid_19_df.Country_code.fillna('OT')

If you have empty strings instead NaN, you can replace them by pd.NA:

covid_19_df.Country_code = covid_19_df.Country_code.replace('', pd.NA).fillna('OT')

Output:

>>> covid_19_df
  Country_code Country
0           OM    Oman
1           OM    Oman
2           OT   Other
3           OT   Other
4           OT   Other