python计算时间差的方法

from dateutil import rrule
import datetime
def weeks_between(start_date, end_date):
  weeks = rrule.rrule(rrule.WEEKLY, dtstart=start_date, until=end_date)
  return weeks.count( )

if _ _name_ _=='_ _main_ _':
  starts = [datetime.date(2005, 01, 04), datetime.date(2005, 01, 03)]
  end = datetime.date(2005, 01, 10)
  for s in starts:
    days = rrule.rrule(rrule.DAILY, dtstart=s, until=end).count( )
    print "%d days shows as %d weeks "% (days, weeks_between(s, end))