【python】python获取当前日期前后N天或N月的日期

 # -*- coding: utf- -*-

 '''获取当前日期前后N天或N月的日期'''

 from time import strftime, localtime
 from datetime import timedelta, date
 import calendar

 year = strftime("%Y",localtime())
 mon  = strftime("%m",localtime())
 day  = strftime("%d",localtime())
 hour = strftime("%H",localtime())
 min  = strftime("%M",localtime())
 sec  = strftime("%S",localtime())

 def today():
     '''''
     get today,date format="YYYY-MM-DD"
     '''''
     return date.today()

 def todaystr():
     '''
     get date string, date format="YYYYMMDD"
     '''
     return year+mon+day

 def datetime():
     '''''
     get datetime,format="YYYY-MM-DD HH:MM:SS"
     '''
     return strftime("%Y-%m-%d %H:%M:%S",localtime())

 def datetimestr():
     '''''
     get datetime string
     date format="YYYYMMDDHHMMSS"
     '''
     return year+mon+day+hour+min+sec

 def get_day_of_day(n=):
     '''''
     if n>=,date is larger than today
     if n<,date is less than today
     date format = "YYYY-MM-DD"
     '''
     if(n<):
         n = abs(n)
         return date.today()-timedelta(days=n)
     else:
         return date.today()+timedelta(days=n)

 def get_days_of_month(year,mon):
     '''''
     get days of month
     '''
     return calendar.monthrange(year, mon)[] 

 def get_firstday_of_month(year,mon):
     '''''
     get the first day of month
     date format = "YYYY-MM-DD"
     '''
     days=""
     if(int(mon)<):
         mon = ""+str(int(mon))
     arr = (year,mon,days)
     return "-".join("%s" %i for i in arr) 

 def get_lastday_of_month(year,mon):
     '''''
     get the last day of month
     date format = "YYYY-MM-DD"
     '''
     days=calendar.monthrange(year, mon)[]
     mon = addzero(mon)
     arr = (year,mon,days)
     return "-".join("%s" %i for i in arr) 

 def get_firstday_month(n=):
     '''''
     get the first day of month from today
     n is how many months
     '''
     (y,m,d) = getyearandmonth(n)
     d = ""
     arr = (y,m,d)
     return "-".join("%s" %i for i in arr) 

 def get_lastday_month(n=):
     '''''
     get the last day of month from today
     n is how many months
     '''
     return "-".join("%s" %i for i in getyearandmonth(n)) 

 def getyearandmonth(n=):
     '''''
     get the year,month,days from today
     befor or after n months
     '''
     thisyear = int(year)
     thismon = int(mon)
     totalmon = thismon+n
     if(n>=):
         if(totalmon<=):
             days = str(get_days_of_month(thisyear,totalmon))
             totalmon = addzero(totalmon)
             return (year,totalmon,days)
         else:
             i = totalmon/
             j = totalmon%
             if(j==):
                 i-=
                 j=
             thisyear += i
             days = str(get_days_of_month(thisyear,j))
             j = addzero(j)
             return (str(thisyear),str(j),days)
     else:
         if((totalmon>) and (totalmon<)):
             days = str(get_days_of_month(thisyear,totalmon))
             totalmon = addzero(totalmon)
             return (year,totalmon,days)
         else:
             i = totalmon/
             j = totalmon%
             if(j==):
                 i-=
                 j=
             thisyear +=i
             days = str(get_days_of_month(thisyear,j))
             j = addzero(j)
             return (str(thisyear),str(j),days) 

 def addzero(n):
     '''''
     add  before -
     return -
     '''
     nabs = abs(int(n))
     if(nabs<):
         return ""+str(nabs)
     else:
         return nabs 

 def get_today_month(n=):
     '''''
     获取当前日期前后N月的日期
     if n>, 获取当前日期前N月的日期
     if n<, 获取当前日期后N月的日期
     date format = "YYYY-MM-DD"
     '''
     (y,m,d) = getyearandmonth(n)
     arr=(y,m,d)
     if(int(day)<int(d)):
         arr = (y,m,day)
     return "-".join("%s" %i for i in arr) 

 if __name__=="__main__":
     print today()
     print todaystr()
     print datetime()
     print datetimestr()
     print get_day_of_day()
     print get_day_of_day(-)
     print get_today_month(-)
     print get_today_month()