Python - 先週の 5 の日付を計算する

第一の方法：

Python代码

from datetime import datetime, timedelta

weekdays = ['月曜日', '火曜日', '水曜日', '木曜日',

'金曜日', '土曜日','日曜日']

def get_previous_byday(dayname, start_date=None):

start_date が None の場合:

start_date = datetime.today()

day_num = start_date.weekday()

day_num_target = weekdays.index(曜日名)

days_ago = (7 + day_num - day_num_target) % 7

if days_ago == 0:

days_ago = 7

target_date = start_date - time delta(days = days_ago)

return target_date

print( datetime. today() )

print( get_previous_byday('Monday') )

print( get_previous_byday('Monday', datetime(2016, 8, 28)) )

第二の方法、dateutil模块

Python代码

from datetime import datetime

from dateutil.relativedelta import relativedelta

from dateutil.rrule import *

d = datetime.now()

print(d)

print(d + relativedelta(weekday= FR))

print(d + relativedelta(weekday=FR(-1)))