Python 日期循环操作的两中方法

import datetimedef main():    begin = datetime.date(2015,4,3)    end = datetime.date(2015,4,15)    for i in range((end - begin).days+1):        day = begin + datetime.timedelta(days=i)        print str(day)

import datetime    begin = datetime.date(2014,6,1)  end = datetime.date(2014,6,7)    d = begin  delta = datetime.timedelta(days=1)  while d <= end:      print d.strftime("%Y-%m-%d")      d += delta