Python之datetime模块的使用

datetime模块的作用

　　datetime模块包含一些函数和类，用户完成日期和时间的解析、格式化和算术运算等。

1、自定义时，分，秒，毫秒，时区参数实例一个time对象的示例

import datetime

t = datetime.time(1, 2, 3)
print(t)
print('hour       :', t.hour)
print('minute     :', t.minute)
print('second     :', t.second)
print('microsecond:', t.microsecond)
print('tzinfo     :', t.tzinfo)
datetime_time.py

运行效果

01:02:03
hour       : 1
minute     : 2
second     : 3
microsecond: 0
tzinfo     : None

2、打印时间最大值和最小值

import datetime

print('时间最小值  :', datetime.time.min)
print('时间最大值  :', datetime.time.max)
print('时间最小值微秒级别 :', datetime.time.resolution)
datetime_time_minmax.py

 运行效果

时间最小值  : 00:00:00
时间最大值  : 23:59:59.999999
时间最小值微秒级别 : 0:00:00.000001

3、利用datetime模块获取当前的年，月，日

import datetime

today = datetime.date.today()
print('今天时间:', today)
print('ordinal:', today.toordinal())
print('Year   :', today.year)
print('Mon    :', today.month)
print('Day    :', today.day)

print('ctime  :', today.ctime())

tt = today.timetuple()
print('tuple  : tm_year  =', tt.tm_year)
print('         tm_mon   =', tt.tm_mon)
print('         tm_mday  =', tt.tm_mday)
print('         tm_hour  =', tt.tm_hour)
print('         tm_min   =', tt.tm_min)
print('         tm_sec   =', tt.tm_sec)
print('         tm_wday  =', tt.tm_wday)
print('         tm_yday  =', tt.tm_yday)
print('         tm_isdst =', tt.tm_isdst)
datetime_date.py

 运行效果

今天时间: 2020-05-20
ordinal: 737565
Year   : 2020
Mon    : 5
Day    : 20
ctime  : Wed May 20 00:00:00 2020
tuple  : tm_year  = 2020
         tm_mon   = 5
         tm_mday  = 20
         tm_hour  = 0
         tm_min   = 0
         tm_sec   = 0
         tm_wday  = 2
         tm_yday  = 141
         tm_isdst = -1

 4、天数每天加1和格式化时间戳的示例

import datetime
import time

o = 733478
print('o               :', o)
print('fromordinal(o)  :', datetime.date.fromordinal(o))


t = time.time()
print('t               :', t)
print('fromtimestamp(t):', datetime.date.fromtimestamp(t))
datetime_date_fromordinal.py

运行效果

o               : 733478
fromordinal(o)  : 2009-03-12
t               : 1589960551.3368747
fromtimestamp(t): 2020-05-20

 5、打印日期的最大值，最小值的示例

import datetime

print('日期最小值  :', datetime.date.min)
print('日期最大值  :', datetime.date.max)
print('精确到时分秒  :', datetime.date.resolution)
datetime_date_minmax.py

运行效果

日期最小值  : 0001-01-01
日期最大值  : 9999-12-31
精确到时分秒  : 1 day, 0:00:00

6、日期时间的替换

import datetime

d1 = datetime.date(2008, 3, 29)
print('d1:', d1.ctime())

d2 = d1.replace(year=2009)
print('d2:', d2.ctime())
datetime_date_replace.py

 运行效果

d1: Sat Mar 29 00:00:00 2008
d2: Sun Mar 29 00:00:00 2009

7、生成日期时间可算术运算的对象

import datetime

print('microseconds:', datetime.timedelta(microseconds=1))
print('milliseconds:', datetime.timedelta(milliseconds=1))
print('seconds     :', datetime.timedelta(seconds=1))
print('minutes     :', datetime.timedelta(minutes=1))
print('hours       :', datetime.timedelta(hours=1))
print('days        :', datetime.timedelta(days=1))
print('weeks       :', datetime.timedelta(weeks=1))
datetime_timedelta.py

运行效果

microseconds: 0:00:00.000001
milliseconds: 0:00:00.001000
seconds     : 0:00:01
minutes     : 0:01:00
hours       : 1:00:00
days        : 1 day, 0:00:00
weeks       : 7 days, 0:00:00

 8、获取指定时间段的秒数

import datetime

for delta in [datetime.timedelta(microseconds=1),
              datetime.timedelta(milliseconds=1),
              datetime.timedelta(seconds=1),
              datetime.timedelta(minutes=1),
              datetime.timedelta(hours=1),
              datetime.timedelta(days=1),
              datetime.timedelta(weeks=1),
              ]:
    print('{:15} = {:8} seconds'.format(
        str(delta), delta.total_seconds())
    )
datetime_timedelta_total_seconds.py

运行效果

0:00:00.000001  =    1e-06 seconds
0:00:00.001000  =    0.001 seconds
0:00:01         =      1.0 seconds
0:01:00         =     60.0 seconds
1:00:00         =   3600.0 seconds
1 day, 0:00:00  =  86400.0 seconds
7 days, 0:00:00 = 604800.0 seconds

9、时间的算术运算 

import datetime

today = datetime.date.today()
print('Today    :', today)

one_day = datetime.timedelta(days=1)
print('One day  :', one_day)

yesterday = today - one_day
print('Yesterday:', yesterday)

tomorrow = today + one_day
print('Tomorrow :', tomorrow)

print()
print('tomorrow - yesterday:', tomorrow - yesterday)
print('yesterday - tomorrow:', yesterday - tomorrow)
datetime_date_math.py

运行效果

Today    : 2020-05-20
One day  : 1 day, 0:00:00
Yesterday: 2020-05-19
Tomorrow : 2020-05-21

tomorrow - yesterday: 2 days, 0:00:00
yesterday - tomorrow: -2 days, 0:00:00

 10、时间的算术浮点运算

import datetime

one_day = datetime.timedelta(days=1)
print('1 day    :', one_day)
print('5 days   :', one_day * 5)
print('1.5 days :', one_day * 1.5)
print('1/4 day  :', one_day / 4)

# assume an hour for lunch
work_day = datetime.timedelta(hours=7)
meeting_length = datetime.timedelta(hours=1)
print('meetings per day :', work_day / meeting_length)
datetime_timedelta_math.py

运行效果

1 day    : 1 day, 0:00:00
5 days   : 5 days, 0:00:00
1.5 days : 1 day, 12:00:00
1/4 day  : 6:00:00
meetings per day : 7.0

11、时间和日期的比较

import datetime
import time

print('Times:')
t1 = datetime.time(12, 55, 0)
print('  t1:', t1)
t2 = datetime.time(13, 5, 0)
print('  t2:', t2)
print('  t1 < t2:', t1 < t2)

print()
print('Dates:')
d1 = datetime.date.today()
print('  d1:', d1)
d2 = datetime.date.today() + datetime.timedelta(days=1)
print('  d2:', d2)
print('  d1 > d2:', d1 > d2)
datetime_comparing.py

运行效果

Times:
  t1: 12:55:00
  t2: 13:05:00
  t1 < t2: True

Dates:
  d1: 2020-05-21
  d2: 2020-05-22
  d1 > d2: False

12、通过反射获取年，月，日，时，分，秒的示例

import datetime

print('Now    :', datetime.datetime.now())
print('Today  :', datetime.datetime.today())
print('UTC Now:', datetime.datetime.utcnow())
print()

FIELDS = [
    'year', 'month', 'day',
    'hour', 'minute', 'second',
    'microsecond',
]

d = datetime.datetime.now()
for attr in FIELDS:
    print('{:15}: {}'.format(attr, getattr(d, attr)))
datetime_datetime.py

运行效果

Now    : 2020-05-21 09:43:57.311893
Today  : 2020-05-21 09:43:57.311894
UTC Now: 2020-05-21 01:43:57.311893

year           : 2020
month          : 5
day            : 21
hour           : 9
minute         : 43
second         : 57
microsecond    : 311893

13、时间和日期的拼接示例

 1 import datetime
 2 
 3 t = datetime.time(1, 2, 3)
 4 print('t :', t)
 5 
 6 d = datetime.date.today()
 7 print('d :', d)
 8 
 9 dt = datetime.datetime.combine(d, t)
10 print('dt:', dt)
datetime_datetime_combine.py

运行效果

t : 01:02:03
d : 2020-05-21
dt: 2020-05-21 01:02:03

14、日期时间的格式化

import datetime

format = "%Y-%m-%d %H:%M:%S"

today = datetime.datetime.today()
print('ISO     :', today)

s = today.strftime(format)
print('strftime:', s)

d = datetime.datetime.strptime(s, format)
print('strptime:', d.strftime(format))
datetime_datetime_strptime.py

运行效果

ISO     : 2020-05-21 09:50:46.448841
strftime: 2020-05-21 09:50:46 
strptime: 2020-05-21 09:50:46

15、格式化的介绍

import datetime

today = datetime.datetime.today()
print('ISO     :', today)
print('format(): {:%Y-%m-%d %H:%M:%S}'.format(today))
datetime_format.py

运行效果

ISO     : 2020-05-21 10:02:14.044698
format(): 2020-05-21 10:02:14
符号注释示例
%a 缩写的星期几 'Wed'
%A 完整的星期几 'Wednesday'
%w 星期几的编号:0(星期天)到6（星期六） '3'
%d 当月哪一天 '13'
%b 缩写的月份名 'Jan'
%B 完整的月份名 'January'
%m 当年哪个月 '01'
%y 不加世纪编号的年份 '16'
%Y 加世纪编号的年份 '2016'
%H 24小时制的小时数 '17'
%I 12小时制的小时数 '05'
%p AM/PM 'PM'
%M 分钟 '00'
%S 秒 '00'
%f 微秒 '000000'
%z 区分时区的日期时间对象的UTC偏移 '-0500'
%Z 时区名 'EST'
%j 当年的哪一天 '013'
%W 当年的哪一周 '02'
%c 当前本地化环境的日期和时间表示 'Wed Jan 13 17:00:00 2016'
%x 当前本地化环境的日期表示 '01/13/16'
%X 当前本地化环境的时间表示 '17:00:00'
%% 字面量%字符 '%'

16、时区的自动转换示例

import datetime

min6 = datetime.timezone(datetime.timedelta(hours=-6))
plus6 = datetime.timezone(datetime.timedelta(hours=6))
d = datetime.datetime.now(min6)

print(min6, ':', d)
print(datetime.timezone.utc, ':',
      d.astimezone(datetime.timezone.utc))
print(plus6, ':', d.astimezone(plus6))

# 转换为当前系统时区
d_system = d.astimezone()
print(d_system.tzinfo, '      :', d_system)
datetime_timezone.py

运行效果

UTC-06:00 : 2020-05-20 20:15:04.716839-06:00
UTC : 2020-05-21 02:15:04.716839+00:00
UTC+06:00 : 2020-05-21 08:15:04.716839+06:00
EST       : 2020-05-21 10:15:04.716839+08:00

17、时间戳转时间的示例

import datetime
ts = 1590017732
ret = datetime.datetime.fromtimestamp(ts)
print(ret)

运行效果

2020-05-21 07:35:32

 18、时间转时间戳的示例

import datetime

d = '2020-05-21 07:35:32'
ret = datetime.datetime.fromisoformat(d).timestamp()
print(ret)

运行效果

1590017732.0
posted @ 2020-05-21 10:31  小粉优化大师  阅读(297)  评论(0)  编辑  收藏  举报