python判断当前时间为星期几

方法一

思路：给定一个历史星期一的时间，然后当前时间减去历史星期一的时间的天数，对7求余

import pandas as pd

timea = '2021-08-01'
s = '2021-08-21'
sub = pd.to_datetime(s) - pd.to_datetime(timea)

print(type(sub), sub, pd.to_datetime(timea))

week = sub.days % 7
week

<class 'pandas._libs.tslibs.timedeltas.Timedelta'> 20 days 00:00:00 2021-08-01 00:00:00
6

0 即为周天

方法二

from datetime import datetime
s = '2021-08-12'
dayOfWeek = datetime.strptime(s, '%Y-%m-%d').isoweekday() # 返回数字1-7代表周一到周日
dayOfWeek