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'