如何比较 python 中的两个日期列

Question

still learning python and have a previous SAS background. Want to compare two date columns and have a string column based on the result.

example is below

essentially, if fee_paid_date is before close date, then say"fee paid before closed" else "fee paid during open"

so here is what i did

main_df["Payment_validity"] = main_df['fee_paid_date'].apply(lambda x: 'Fee paid while open' if x <=main_df['PACKAGE_D_CLOSE'] else 'Fee paid after closed ')

and i get the following error:

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

Any help is much appreciated

Answer 1

Use axis=1 to tell do the apply row wise

main_df["Payment_validity"] = main_df[['PACKAGE_D_CLOSE','fee_paid_date']].apply(lambda x: 'Fee paid while open' if x[1] <= x[0] else 'Fee paid after closed ', axis=1)

NOTE: assuming PACKAGE_D_CLOSE and fee_paid_date are datetime object not string .

You can cast them to datetime by simply

main_df['fee_paid_date'] = pd.to_datetime(main_df['fee_paid_date'])
main_df['PACKAGE_D_CLOSE'] = pd.to_datetime(main_df['PACKAGE_D_CLOSE'])