If you are using
This is minimal working example:
inplace=True
you don't need to assign the result. Remove inplace=True
in your code, or print(data_pd)
. result variable is None, because when inplace=true
.fillna
method returns None
.This is minimal working example:
import pandas as pd df = pd.DataFrame({'date': ['2001-09-01', '2001-09-02', '2001-10-01', '2001-10-03', '2001-09-03'], 'value': [1, 2, 0, None, None]}) df.date = pd.to_datetime(df.date) df.fillna(df.groupby([df.date.dt.year, df.date.dt.month]).transform('mean'), inplace=True)