Get week start date (Monday) from a date column in Python (pandas)?

Question

I have seen a lot of posts about how you can do it with a date string but I am trying something for a dataframe column and haven\'t got any luck so far. My current method is

Answer 1

from datetime import datetime, timedelta

# Convert column to pandas datetime equivalent
df['myday'] = pd.to_datetime(df['myday']) 

# Create function to calculate Start Week date
week_start_date = lambda date: date - timedelta(days=date.weekday())

# Apply above function on DataFrame column
df['week_start_date'] = df['myday'].apply(week_start_date)