# -*- encoding: utf-8 -*-

import datetime


def isoformat(time):
 '''
 将datetime或者timedelta对象转换成ISO 8601时间标准格式字符串
 :param time: 给定datetime或者timedelta
 :return: 根据ISO 8601时间标准格式进行输出
 '''
 if isinstance(time, datetime.datetime): # 如果输入是datetime
  return time.isoformat();
 elif isinstance(time, datetime.timedelta): # 如果输入时timedelta，计算其代表的时分秒
  hours = time.seconds // 3600
  minutes = time.seconds % 3600 // 60
  seconds = time.seconds % 3600 % 60
  return 'P%sDT%sH%sM%sS' % (time.days, hours, minutes, seconds) # 将字符串进行连接


if __name__ == '__main__':
 dtnow = datetime.datetime.now() # 获取现在时间
 print(isoformat(dtnow))

 dtpast = datetime.datetime(1990, 12, 31) # 获取过去某个时间点
 print(isoformat(dtpast))

 interval = dtnow - dtpast # 得到时间差
 print(interval)
 print(isoformat(interval))

2017-01-14T10:54:28.323000
1990-12-31T00:00:00
9511 days, 10:54:28.323000
P9511DT10H54M28S