计算从今天起上一个月的日期

 1 from datetime import *
 2 import calendar
 3 
 4 def get_monthago_date():
 5     nowtime = date.today()
 6     nowtime_year = nowtime.year
 7     nowtime_month = nowtime.month
 8     nowtime_day = nowtime.day
 9     
10     onemonthago = nowtime_month - 1    #减去一个月，判断是否为0，为0表示当前月份是1月份
11     
12     if onemonthago == 0:    #如果当前月份为1月份，就需要设置年份减去1，月份为12月
13         oneyearago = nowtime_year - 1
14         onemonthago = 12
15         monthindex, monthdays = calendar.monthrange(oneyearago, onemonthago)    #获取上一个月有多少天
16         
17         if monthdays >= nowtime_day:    #如果上一个月的总天数大于当前日期就用当前的日期
18             onemonthdate = nowtime.replace(year=oneyearago, month=onemonthago, day=nowtime_day)
19         else:    #如果上一个月的总天数都小于当前的日期(2月28和3.31这种情况)就使用上个月的最大日期
20             onemonthdate = nowtime.replace(year=oneyearago, month=onemonthago, day=monthdays)
21             
22         return onemonthdate.strftime(‘%Y-%m-%d‘)
23     else:
24         monthindex, monthdays = calendar.monthrange(nowtime_year, onemonthago)
25         
26         if monthdays >= nowtime_day:
27             onemonthdate = nowtime.replace(year=nowtime_year, month=onemonthago, day=nowtime_day)
28         else:
29             onemonthdate = nowtime.replace(year=nowtime_year, month=onemonthago, day=monthdays)
30             
31         return onemonthdate.strftime(‘%Y-%m-%d‘)