Get weekday/day-of-week for Datetime column of DataFrame

Question

I have a DataFrame df like the following (excerpt, \'Timestamp\' are the index):

Timestamp              Value
2012-06-01 00:00:00     100
2012-0         


        

Answer 1

If the Timestamp column is a datetime value, then you can just use:
df['weekday'] = df['Timestamp'].apply(lambda x: x.weekday())

or

df['weekday'] = pd.to_datetime(df['Timestamp']).apply(lambda x: x.weekday())