Day5模块-time和datetime模块

模块是封装一段代码来实现某种功能。

分为三类：

1.自定义模块

2.标准库，内置模块

3.开源模块

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1.time模块

 >>> import time
 #返回处理器时间,3.3后变成了time.process_time()测量处理器运算时间,不包括sleep时间,不稳定
 >>> print(time.clock())
 2.9933526190766363e-06
 >>> print(time.process_time())
 0.09360059999999999

 #返回与utc时间的时间差,以秒计算\
 >>> print(time.altzone)
 -32400
 #本地时间
 >>> print(time.localtime())
 time.struct_time(tm_year=2017, tm_mon=5, tm_mday=21, tm_hour=20, tm_min=54, tm_s
 ec=47, tm_wday=6, tm_yday=141, tm_isdst=0)
 #返回utc时间的struc时间对象格式
 >>> print(time.gmtime(time.time()-800000))
 time.struct_time(tm_year=2017, tm_mon=5, tm_mday=12, tm_hour=6, tm_min=41, tm_se
 c=56, tm_wday=4, tm_yday=132, tm_isdst=0)
 #返回时间格式
 >>> print(time.asctime())
 Sun May 21 20:56:26 2017
 >>> print(time.asctime(time.localtime()))
 Sun May 21 20:55:55 2017

日期字符串转换为时间戳

 #将字符串转换成struct对象
 >>> string_2_struct = time.strptime("2016/05/22","%Y/%m/%d")
 >>> print(string_2_struct)
 time.struct_time(tm_year=2016, tm_mon=5, tm_mday=22, tm_hour=0, tm_min=0, tm_sec
 =0, tm_wday=6, tm_yday=143, tm_isdst=-1)
 >>>
 #将struct对象转换为时间戳对象
 >>> string_2_stamp = time.mktime(string_2_struct)
 >>> print(string_2_stamp)
 1463846400.0

时间戳转换为字符串

 >>> print(time.time()) #当前utc时间，时间是秒
 1495372102.3229373
 >>> print(time.gmtime()) #struct对象的时间格式
 time.struct_time(tm_year=2017, tm_mon=5, tm_mday=21, tm_hour=13, tm_min=8, tm_se
 c=29, tm_wday=6, tm_yday=141, tm_isdst=0)

 #将utc时间戳转换成struct_time格式
 >>> print(time.gmtime(time.time()-86640))
 time.struct_time(tm_year=2017, tm_mon=5, tm_mday=20, tm_hour=13, tm_min=1, tm_se
 c=42, tm_wday=5, tm_yday=140, tm_isdst=0)
 #将utc struct_time格式转成指定的字符串格式
 >>> print(time.strftime("%Y-%m-%d %H:%M:%S",time.gmtime()))
 2017-05-21 13:07:45

时间加减

 >>> import datetime
 >>> print("datetime".center(50,'*'))
 *********************datetime*********************
 >>> print(datetime.datetime.now()) #返回当前时间
 2017-05-21 21:12:10.507988
 # 时间戳直接转成日期格式 2016-08-19
 >>> print(datetime.date.fromtimestamp(time.time()))
 2017-05-21

 #返回当前时间
 >>> print(datetime.datetime.now())
 2017-05-21 21:17:05.163842
 #时间戳直接转成日期格式 2016-08-19
 >>> print(datetime.date.fromtimestamp(time.time()))
 2017-05-21
 #当前时间加3天
 >>> print(datetime.datetime.now()+datetime.timedelta(3))
 2017-05-24 21:17:39.092782
 #当前时间减3天
 >>> print(datetime.datetime.now()+datetime.timedelta(-3))
 2017-05-18 21:17:46.039180
 #当前时间加3小时
 >>> print(datetime.datetime.now()+datetime.timedelta(hours=3))
 2017-05-22 00:18:01.337055
 #当前时间加30分钟
 >>> print(datetime.datetime.now()+datetime.timedelta(minutes=30))
 2017-05-21 21:49:16.833373

时间替换

 >>> c_time = datetime.datetime.now()
 >>> print(c_time.replace(minute=3,hour=2))
 2017-05-21 02:03:05.940477
 >>> print(datetime.datetime.now)
 <built-in method now of type object at 0x0000000067D262C0>
 >>> print(datetime.datetime.now())
 2017-05-21 21:23:49.137948

Directive	Meaning	Notes
%a	Locale’s abbreviated weekday name.
%A	Locale’s full weekday name.
%b	Locale’s abbreviated month name.
%B	Locale’s full month name.
%c	Locale’s appropriate date and time representation.
%d	Day of the month as a decimal number [01,31].
%H	Hour (24-hour clock) as a decimal number [00,23].
%I	Hour (12-hour clock) as a decimal number [01,12].
%j	Day of the year as a decimal number [001,366].
%m	Month as a decimal number [01,12].
%M	Minute as a decimal number [00,59].
%p	Locale’s equivalent of either AM or PM.	(1)
%S	Second as a decimal number [00,61].	(2)
%U	Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0.	(3)
%w	Weekday as a decimal number [0(Sunday),6].
%W	Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0.	(3)
%x	Locale’s appropriate date representation.
%X	Locale’s appropriate time representation.
%y	Year without century as a decimal number [00,99].
%Y	Year with century as a decimal number.
%z	Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59].
%Z	Time zone name (no characters if no time zone exists).
%%	A literal '%' character.

字符串、时间格式、utc时间的转换关系

a.字符串转换为utc时间

>>> time.strptime("2016/05/22","%Y/%m/%d")
time.struct_time(tm_year=2016, tm_mon=5, tm_mday=22, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=6, tm_yday=143, tm_isdst=-1)

>>> struct_time = time.strptime("2016/05/22","%Y/%m/%d")
>>> time.mktime(struct_time)
1463846400.0

b.utc时间转换为字符串

>>> time.gmtime(1463846400.0)
time.struct_time(tm_year=2016, tm_mon=5, tm_mday=21, tm_hour=16, tm_min=0, tm_se
c=0, tm_wday=5, tm_yday=142, tm_isdst=0)

>>> time.strftime("%Y-%m-%d %H:%M:%S",time.gmtime())
'2017-05-21 13:30:47'