Pandas pd.isnull() function

Question

I need to replace not null values in my dataframe with 1 and null values with 0.

Here is my dataframe:

my_list= [['a','b','c'],['test1','test2',None],[None,'101','000']]

mydf= pd.DataFrame(my_list,columns=['col1','col2','col3'])

mydf

    col1   col2  col3
0      a      b     c
1  test1  test2  None
2   None    101   000

mydf.where((pd.isnull(mydf)),0,inplace=True)

mydf

   col1 col2  col3
0     0    0     0
1     0    0  None
2  None    0     0

I am not sure why it is replacing not null values with zero. pd.notnull() does the opposite. Can anyone explain what I am missing here?

Answer 1

Just do:

mydf = mydf.notnull() * 1
mydf

For completeness

mydf.isnull() * 1