获取上个月的今天

from datetime import datetime,timedelta
from dateutil.relativedelta import relativedelta
def day_last_mn(today):
	today = datetime.strptime(today, "%Y-%m-%d")
	endDayOfLastMonth = today - relativedelta(months=1)
	return datetime.strftime(endDayOfLastMonth, "%Y-%m-%d")
print(day_last_mn("2022-03-31"))

结果
2022-02-28