模块 - time/datetime

time 模块

time模块方法：

>>> import time
>>> time.time()               #时间戳 秒级别
1519212085.6211221            #从1970年到现在一共度过1519212085秒；
>>> time.time()/3600/24/365   #48年 1970-2018年有这么多秒 1h=3600s
48.17390346104816
>>> time.localtime()          #本地时间
time.struct_time(tm_year=2018, tm_mon=2, tm_mday=21, tm_hour=20, tm_min=8, tm_sec=33, tm_wday=2, tm_yday=52, tm_isdst=0)
>>> time.localtime(2342342434)
time.struct_time(tm_year=2044, tm_mon=3, tm_mday=23, tm_hour=18, tm_min=40, tm_sec=34, tm_wday=2, tm_yday=83, tm_isdst=0)
>>> a=time.localtime()
>>> a
time.struct_time(tm_year=2018, tm_mon=2, tm_mday=21, tm_hour=19, tm_min=28, tm_sec=45, tm_wday=2, tm_yday=52, tm_isdst=0)
>>> '%s-%s-%d'%(a.tm_year,a.tm_mon,a.tm_mday)
'2018-2-21'
>>> time.mktime(a)            #把localtime()时间反转时间成时间戳
1519214861.0 

0  tm_year    #年 1970-2018
1  tm_mon     #月 1-12
2  tm_mday    #日 1-31
3  tm_hour    #时 0-23
4  tm_min     #分 0-59
5  tm_sec     #秒 0-59
6  tm_wday    #一周中得第几天 0-6
7  tm_yday    #一年中得第几天 0-365
8  tm_isdst   #是否是夏令时  0-1

>>> time.gmtime()     #比北京时间晚8点 UTC时区（0时区）
time.struct_time(tm_year=2018, tm_mon=2, tm_mday=21, tm_hour=11, tm_min=50, tm_sec=46, tm_wday=2, tm_yday=52, tm_isdst=0)
>>> time.sleep(2)     #睡一会 单位为 秒
>>> time.asctime()    #表示时间得另外一种方法
'Wed Feb 21 20:53:43 2018'
>>> time.ctime()      #表示时间得另外一种方法
'Wed Feb 21 20:57:16 2018'
>>> time.ctime(3123)
'Thu Jan  1 08:52:03 1970'
>>> time.ctime(0)
'Thu Jan  1 08:00:00 1970'
>>> time.strftime('%Y-%m-%d %H:%M:%S')      #表示时间 字符串
'2018-02-21 21:04:48'
>>> a=time.localtime(2432423423)
>>> a
time.struct_time(tm_year=2047, tm_mon=1, tm_mday=30, tm_hour=9, tm_min=10, tm_sec=23, tm_wday=2, tm_yday=30, tm_isdst=0)
>>> time.strftime('%Y-%m-%d %H:%M:%S',a)     #表示某一时间戳得 字符串
'2047-01-30 09:10:23'
>>> time.strftime('%Y-%m-%d %H:%M:%S %a',a)  #a 周几
'2047-01-30 09:10:23 Wed'
>>> time.strftime('%Y-%m-%d %H:%M:%S %A',a)  #A 周几
'2047-01-30 09:10:23 Wednesday'
>>> time.strftime('%y-%m-%d %H:%M:%S %b')    #b 月
'18-02-21 21:22:19 Feb'
>>> time.strftime('%y-%m-%d %H:%M:%S %B')    #B 月
'18-02-21 21:22:29 February'
>>> time.strftime('%Y-%m-%d %H:%M:%S %p',a)  #p 上午下午
'2047-01-30 09:10:23 AM'
>>> time.strftime('%Y-%m-%d %H:%M:%S %U')    #U 一年得第几周
'2018-02-21 21:08:15 07'
>>> time.strftime('%Y-%m-%d %H:%M:%S %w')    #w 一周得第几天
'2018-02-21 21:09:55 3'
>>> time.strftime('%y-%m-%d %H:%M:%S %z')    #z 东8区时间
'18-02-21 21:10:38 +0800'
>> time.strftime('%Y-%m-%d %H:%M:%S %Z')     #Z 时间标准
'2018-02-21 21:28:22 中国标准时间'

>>> s=time.strftime('%Y-%m-%d %H:%M:%S')     #时间字符串 格式  时间戳来回转换
>>> s
'2018-02-21 21:32:19'
>>> s2= time.strptime(s,'%Y-%m-%d %H:%M:%S')
>>> s2
time.struct_time(tm_year=2018, tm_mon=2, tm_mday=21, tm_hour=21, tm_min=32, tm_sec=19, tm_wday=2, tm_yday=52, tm_isdst=-1)
>>> time.mktime(s2)
1519219939.0

字符串转时间格式对应表
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.

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总结：time模块
1.time.time()
2.time.localtime()
3.time.localtime(2342342434)
4.time.mktime(a)
5.time.gmtime()
6.time.sleep(2)
7.time.asctime()
8.time.ctime()
9.time.ctime(3123)
10.time.strftime('%Y-%m-%d %H:%M:%S')
11.time.strftime('%Y-%m-%d %H:%M:%S',a)
12.time.strftime('%Y-%m-%d %H:%M:%S %A',a)
13.time.strptime(s,'%Y-%m-%d %H:%M:%S')

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datetime模块

相比于time模块 datetime模块得接口更直观更容易调用 重点是进行时间运算

方法：
>>> a=datetime.datetime.now()
>>> a
datetime.datetime(2018, 2, 21, 21, 59, 57, 526811)
>>> a.year
2018
>>> a.timetuple()
time.struct_time(tm_year=2018, tm_mon=2, tm_mday=21, tm_hour=21, tm_min=59, tm_sec=57, tm_wday=2, tm_yday=52, tm_isdst=-1)
>>> d2=datetime.date.fromtimestamp(time.time())       #根据时间戳快速拿到年月日
>>> d2
datetime.date(2018, 2, 21)
>>> d2.timetuple()        #注意 时分秒 丢了
time.struct_time(tm_year=2018, tm_mon=2, tm_mday=21, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=2, tm_yday=52, tm_isdst=-1)

时间运算：
>>> datetime.datetime.now()-datetime.timedelta(days=1)
datetime.datetime(2018, 2, 20, 22, 13, 4, 891830)
>>> datetime.datetime.now()-datetime.timedelta(days=3)
datetime.datetime(2018, 2, 18, 22, 14, 7, 771268)
>>> datetime.datetime.now()-datetime.timedelta(hours=3)
datetime.datetime(2018, 2, 21, 19, 14, 33, 758609)
>>> datetime.datetime.now()+datetime.timedelta(hours=3)
datetime.datetime(2018, 2, 22, 1, 14, 48, 426850)
>>> datetime.datetime.now()+datetime.timedelta(minutes=10)
datetime.datetime(2018, 2, 21, 22, 25, 32, 615892)
>>> datetime.datetime.now()+datetime.timedelta(seconds=10)
datetime.datetime(2018, 2, 21, 22, 16, 29, 661140) 

时间替换：
>>> s=datetime.datetime.now()
>>> s
datetime.datetime(2018, 2, 21, 22, 21, 34, 62949)
>>> s.replace(year=2016)
datetime.datetime(2016, 2, 21, 22, 21, 34, 62949)
>>> s.replace(year=2016,month=8)
datetime.datetime(2016, 8, 21, 22, 21, 34, 62949)
>>> s.replace(year=2016,month=8,day=2)
datetime.datetime(2016, 8, 2, 22, 21, 34, 62949) 

总结：
1.方法：a=datetime.datetime.now() a.year a.timetuple() d2=datetime.date.fromtimestamp(time.time())
2.时间运算：datetime.datetime.now()-datetime.timedelta(days=3)
3.时间替换：s=datetime.datetime.now() s.replace(year=2016,month=8)

补充：

#把datetime转成字符串
def datetime_toString(dt):
    return dt.strftime("%Y-%m-%d-%H")

#把字符串转成datetime
def string_toDatetime(string):
    return datetime.strptime(string, "%Y-%m-%d-%H")

#把字符串转成时间戳形式
def string_toTimestamp(strTime):
    return time.mktime(string_toDatetime(strTime).timetuple())

#把时间戳转成字符串形式
def timestamp_toString(stamp):
    return time.strftime("%Y-%m-%d-%H", tiem.localtime(stamp))

#把datetime类型转外时间戳形式
def datetime_toTimestamp(dateTim):
    return time.mktime(dateTim.timetuple())

#coding=utf-8
import time
import datetime

def yes_time():
    #获取当前时间
    now_time = datetime.datetime.now()
    #当前时间减去一天 获得昨天当前时间
    yes_time = now_time + datetime.timedelta(days=-1)
    #格式化输出
    yes_time_str = yes_time.strftime('%Y-%m-%d %H:%M:%S')
    print yes_time_str  # 2017-11-01 22:56:02

def dif_time():
    #计算两个时间之间差值
    now_time = datetime.datetime.now()
    now_time = now_time.strftime('%Y-%m-%d %H:%M:%S')
    d1 = datetime.datetime.strptime('2017-10-16 19:21:22', '%Y-%m-%d %H:%M:%S')
    d2 = datetime.datetime.strptime(now_time, '%Y-%m-%d %H:%M:%S')
    #间隔天数
    day = (d2 - d1).days
    #间隔秒数
    second = (d2 - d1).seconds
    print day   #
    print second  #13475  注意这样计算出的秒数只有小时之后的计算额 也就是不包含天之间差数

def unix_time():
    #将python的datetime转换为unix时间戳
    dtime = datetime.datetime.now()
    un_time = time.mktime(dtime.timetuple())
    print un_time  #1509636609.0
    #将unix时间戳转换为python  的datetime
    unix_ts = 1509636585.0
    times = datetime.datetime.fromtimestamp(unix_ts)
    print times  #2017-11-02 23:29:45