python获取当前日期前后N天或N月的日期

#!/usr/bin/python''' Filename: "utildate.py"author: "zhangsong"date : "2009-03-24"version: "1.00"'''from time import strftime, localtimefrom datetime import timedelta, dateimport calendaryear = 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+daydef 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+secdef getdayofday(n=0): ''' if n>=0,date is larger than today if n<0,date is less than today date format = "YYYY-MM-DD" ''' if(n<0): n = abs(n) return date.today()-timedelta(days=n) else: return date.today()+timedelta(days=n)def getdaysofmonth(year,mon): ''' get days of month ''' return calendar.monthrange(year, mon)[1]def getfirstdayofmonth(year,mon): ''' get the first day of month date format = "YYYY-MM-DD" ''' days="01" if(int(mon)<10): mon = "0"+str(int(mon)) arr = (year,mon,days) return "-".join("%s" %i for i in arr)def getlastdayofmonth(year,mon): ''' get the last day of month date format = "YYYY-MM-DD" ''' days=calendar.monthrange(year, mon)[1] mon = addzero(mon) arr = (year,mon,days) return "-".join("%s" %i for i in arr)def get_firstday_month(n=0): ''' get the first day of month from today n is how many months ''' (y,m,d) = getyearandmonth(n) d = "01" arr = (y,m,d) return "-".join("%s" %i for i in arr)def get_lastday_month(n=0): ''' get the last day of month from today n is how many months ''' return "-".join("%s" %i for i in getyearandmonth(n)) def get_today_month(n=0): ''' get last or next month's today n is how many months 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)def getyearandmonth(n=0): ''' get the year,month,days from today befor or after n months ''' thisyear = int(year) thismon = int(mon) totalmon = thismon+n if(n>=0): if(totalmon<=12): days = str(getdaysofmonth(thisyear,totalmon)) totalmon = addzero(totalmon) return (year,totalmon,days) else: i = totalmon/12 j = totalmon%12 if(j==0): i-=1 j=12 thisyear += i days = str(getdaysofmonth(thisyear,j)) j = addzero(j) return (str(thisyear),str(j),days) else: if((totalmon>0) and (totalmon<12)): days = str(getdaysofmonth(thisyear,totalmon)) totalmon = addzero(totalmon) return (year,totalmon,days) else: i = totalmon/12 j = totalmon%12 if(j==0): i-=1 j=12 thisyear +=i days = str(getdaysofmonth(thisyear,j)) j = addzero(j) return (str(thisyear),str(j),days)def addzero(n): ''' add 0 before 0-9 return 01-09 ''' nabs = abs(int(n)) if(nabs<10): return "0"+str(nabs) else: return nabs#print today()#print addzero(10)print get_today_month(-1)print get_lastday_month(3)print get_firstday_month(3)