该
datetime模块将为您完成所有工作：
>>> import datetime>>> a = datetime.datetime.now()>>> # ...wait a while...>>> b = datetime.datetime.now()>>> print(b-a)0:03:43.984000
如果您不想显示微秒，请使用（如gnibbler建议）：
>>> a = datetime.datetime.now().replace(microsecond=0)>>> b = datetime.datetime.now().replace(microsecond=0)>>> print(b-a)0:03:43
