输入:20170320,输出:20170220
1 import datetime 2 def get_lastmonth(): 3 date = raw_input('please input a date: ') 4 if len(date) == 8: 5 newdate = date[0:4] + '-' + date[4:6] + '-' + date[6:] 6 datestr = datetime.datetime.strptime(newdate, "%Y-%m-%d").date() 7 year = datestr.year 8 month = datestr.month 9 day = datestr.day 10 if month == 1: 11 month = 12 12 year -= 1 13 else: 14 month -= 1 15 lastmonth = datetime.datetime(year, month, day).strftime("%Y-%m-%d") 16 final = ''.join(lastmonth.split('-')) 17 return final 18 else: 19 return None 20 21 print get_lastmonth()