pandas fillna not working

Question

I have a dataframe with nans in it:

>>>df.head()
Out[1]: 
            JPM US SMALLER COMPANIES C ACC
1990-01-02                             NaN
1990         


        

Answer 1

you need inplace

df[1].fillna(0, inplace=True)

Answer 2

You need to assign the value df = df.fillna( t )

Answer 3

You have two options:

1) Specific for each column

cols_fillna = ['column1','column2','column3']
# replace 'NaN' with zero in these columns
 for col in cols_fillna:
     df[col].fillna(0,inplace=True)
     df[col].fillna(0,inplace=True)

2) For the entire dataframe

df = df.fillna(0)