Python模块-datetime模块

datetime.datetime.now() 返回当前的datetime日期类型

>>> d=datetime.datetime.now()
>>> d
datetime.datetime(2018, 2, 17, 17, 41, 49, 372222)
>>> d.year
2018
>>> d.month
2
>>> d.timetuple()
time.struct_time(tm_year=2018, tm_mon=2, tm_mday=17, tm_hour=17, tm_min=41, tm_sec=49, tm_wday=5, tm_yday=48, tm_isdst=-1)
>>> d.timestamp() #转换为时间戳
1518860509.372222
>>> d.replace(year=1997,month=9,day=21) #时间替换
datetime.datetime(1997, 9, 21, 17, 41, 49, 372222)

datetime.date.fromtimestamp() 把一个时间戳转为datetime日期类型

>>> datetime.date.fromtimestamp(1518860509.372222)
datetime.date(2018, 2, 17)

datetime.timedelta：表示时间间隔，即两个时间点之间的长度

>>> datetime.datetime.now()
datetime.datetime(2018, 2, 17, 17, 49, 32, 336825)
>>> datetime.datetime.now() - datetime.timedelta(3) #如果没有指定，默认为3天
datetime.datetime(2018, 2, 14, 17, 49, 56, 980665)
>>> datetime.datetime.now() - datetime.timedelta(days=3) #减去3天
datetime.datetime(2018, 2, 14, 17, 50, 9, 23454)
>>> datetime.datetime.now() + datetime.timedelta(hours=3) #加3个小时
datetime.datetime(2018, 2, 17, 20, 50, 19, 688480