import datetime

import time

#获取当前时间

datetime.datetime.now()

#获取当前日期

datetime.date.today()

#字符串转换为时间格式

>>> t = time.strptime("2009-08-08", "%Y-%m-%d")

>>> y,m,d = t[0:3]

>>> datetime.date(y,m,d)

datetime.date(2009, 8, 8)

>>> datetime.datetime(y,m,d)

datetime.datetime(2009, 8, 8, 0, 0)

#返回前一天的日期

>>> import datetime

>>> today = datetime.date.today()

>>> days = datetime.timedelta(days=1)

>>> print today

2010-04-15

>>> print days

1 day, 0:00:00

>>> print today-days

2010-04-14

>>>

#datetime 对象获取当天日期

>>> now = datetime.datetime.now()

>>> today = now.date().today()

>>> print today

2010-04-15

>>> print now

2010-04-15 14:41:21.421000

获取时间戳

>>> time.time()

1446885023.80355

时间戳转换时间

>>> time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time()))

'2015-11-07 16:32:45'

时间转换时间戳

>>> time.mktime(time.strptime('2015-11-06 16:30:00','%Y-%m-%d %H:%M:%S'))

1446798600.0

获取年与日时分秒

>>> time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())

'2015-11-07 16:45:46'

>>> print (time.strftime("%Y-%m-%d %X", time.localtime()))

2015-11-07 16:52:31

 

获取微妙（百万分之一秒）

>>> datetime.datetime.now().microsecond 

327545

获取时间+微秒数

>>> now = datetime.datetime.now()

>>> "%s.%s" % (now.strftime('%Y%m%d%H%M%S'), now.microsecond)

'20151107172412.390765'

 

Python格式化日期时间的函数为datetime.datetime.strftime()；由字符串转为日期型的函数为：datetime.datetime.strptime()，两个函数都涉及日期时间的格式化字符串，列举如下：

%a Abbreviated weekday name

%A Full weekday name

%b Abbreviated month name

%B Full month name

%c Date and time representation appropriate for locale

%d Day of month as decimal number (01 - 31)

%H Hour in 24-hour format (00 - 23)

%I Hour in 12-hour format (01 - 12)

%j Day of year as decimal number (001 - 366)

%m Month as decimal number (01 - 12)

%M Minute as decimal number (00 - 59)

%p Current locale's A.M./P.M. indicator for 12-hour clock

%S Second as decimal number (00 - 59)

%U Week of year as decimal number, with Sunday as first day of week (00 - 51)

%w Weekday as decimal number (0 - 6; Sunday is 0)

%W Week of year as decimal number, with Monday as first day of week (00 - 51)

%x Date representation for current locale

%X Time representation for current locale

%y Year without century, as decimal number (00 - 99)

%Y Year with century, as decimal number

%z, %Z Time-zone name or abbreviation; no characters if time zone is unknown

%% Percent sign

例子：

字符串转换成datetime

>>> c = datetime.datetime.strptime('Sep-21-09 16:34','%b-%d-%y %H:%M');

>>> c

datetime.datetime(2009, 9, 21, 16, 34)

datetime转换成字符串

>>> datetime.datetime.now().strftime('%b-%d-%y %H:%M:%S');

'Sep-22-09 16:48:08'