pyhton 获得前几个月

#! /usr/bin/python# -*- coding: utf-8 -*-import sysimport timeimport datetimeimport sysreload(sys)sys.setdefaultencoding("utf-8")def getLastMonth(day = None, months=1):    if day:        today = day    else:        today = datetime.date.today()        y = int(months/12)    m = months%12    if today.month - m <= 0:        y = y + 1        m = 12 + (today.month-m)        nextMonth = today.replace(year=today.year-y, month=m, day=1)    elif m == 0:        nextMonth = today.replace(year=today.year-y, day=1)    else:        nextMonth = today.replace(year=today.year-y, month=today.month-m, day=1)    return nextMonthd = datetime.date.today()d=getLastMonth()print d.strftime("%Y-%m-01")d = datetime.date.today()for i in (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15):    d=getLastMonth(day = d, months=11)    print d.strftime("%Y-%m-01")print "............................."d = datetime.date(2011, 1, 1)for i in (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15):    d=getLastMonth(day = d, months=11)    print d.strftime("%Y-%m-01")