time

python时间和日历处理

1. datetime.date类
   导入date模块: from datetime import date

   • ctime(self) return ctime style string.

     >>> date(2017, 5, 15).ctime()
     'Mon May 15 00:00:00 2017'
     

   • fromtimestamp(cls, timestamp) local date from a POSIX timestamp.

     >>> date.fromtimestamp(1494830875.615)
     datetime.date(2017, 5, 15)
     

   • isocalendar(self) return a 3-tuple containing ISO year, week number, and weekday.

     >>> date(2017, 5, 15).isocalendar()
     (2017, 20, 1)
     

   • isoformat(self) return string in ISO 8601 format, YYYY-MM-DD.

      >>> date(2017, 5, 15).isoformat()
      '2017-05-15'
     

   • isoweekday(self) return the day of the week represented by the date. Monday1 ... Sunday7.

     >>> date(2017, 5, 15).isoweekday()
     1
     

   • replace(self, year=None, month=None, day=None) return date with new specified fields.

     >>> date(2017, 5, 15).replace(day=10)
     datetime.date(2017, 5, 10)
     

   • strftime(self, format) return format style string.

     >>> date(2017, 5, 15).strftime("%Y-%m-%d")
     '2017-05-15'
     

   • timetuple(self) return time tuple. compatible with time.localtime().

     >>> date(2017, 5, 15).timetuple()
     time.struct_time(tm_year=2017, tm_mon=5, tm_mday=15, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=135, tm_isdst=-1)
     

   • today(cls) return current date or datetime.

     >>> date.today()
     datetime.date(2017, 5, 15
     

   • weekday(self) return the day of week represented by the date. Monday0 ... Sunday6.

     >>> date(2017,5,15).weekday()
     0
     

2. datetime.time类
   导入time类: from datetime import time

   • isoformat(self) return string in ISO 8601 format, HH:MM:SS[.mmmmmm].

     >>> time(15,13,30).isoformat()
     '15:13:30'
     

   • replace(self, hour=None, minute=None, second=None, microsecond=None, tzinfo=None) return time with new specified fields

     >>> time(15,13,30, 599).replace(second=10)
     datetime.time(15, 13, 10, 599)
     

   • strftime(self, format) return format style string.

     >>> time(15,13,30, 599).strftime("%H:%M:%S")
     '15:13:30'
     

3. datetime.datetime类
   导入datetime类: from datetime import datetime, date, time

   • combine(cls, date, time) return date + time.

     >>> datetime.combine(date(2017, 5, 15), time(15, 36, 20))
     datetime.datetime(2017, 5, 15, 15, 36, 20)
     

   • ctime(self) return ctime style string.

     >>> datetime(2017, 5, 15, 15, 25, 20).ctime()
     'Mon May 15 15:25:20 2017'
     

   • date(self) return date object with same year, month and day.

     >>> datetime(2017, 5, 15, 15, 25, 20).date()
     datetime.date(2017, 5, 15)
     

   • fromtimestamp(self, timestamp) return local time from POSIX timestamp.

     >>> datetime.fromtimestamp(1494833491.141)
     datetime.datetime(2017, 5, 15, 15, 31, 22, 68000)
     

   • isoformat(self, sep='T') return string in ISO 8601 format, YYY-MM-DDTHH:MM:SS[.mmmmmm]. sep is used to separate the year from time. and defaults to "T".

     >>> datetime(2017, 5, 15, 15, 26, 20).isoformat(sep="T")
     '2017-05-15T15:26:20'
     

   • now(cls, tz=None) return local date and time.

     >>> datetime.now()
     datetime.datetime(2017, 5, 15, 15, 38, 25, 563000)
     

   • replace(self, year=None, month=None, day=None, hour=None, minute=None, second=None, microsecond=None, tzinfo=None) return datetime with new specified fields.

     >>> datetime(2017, 5, 15, 15, 29, 30).replace(year=2019, month=2)
     datetime.datetime(2019, 2, 15, 15, 29, 30)
     

   • strptime(cls, date_string, format) return new datetime parsed from a string.

     >>> datetime.strptime("2017-05-15 15:20:20", "%Y-%m-%d %H:%M:%S")
     datetime.datetime(2017, 5, 15, 15, 20, 20)
     

   • time(self) return time object with same time but with tzinfo=None.

     >>> datetime(2017, 5, 15, 15, 29, 30).time()
     datetime.time(15, 29, 30)
     

   • timetuple(self) return time tuple.

     >>> datetime(2017, 5, 15, 15, 29, 30).timetuple()
     time.struct_time(tm_year=2017, tm_mon=5, tm_mday=15, tm_hour=15, tm_min=29, tm_sec=30, tm_wday=0, tm_yday=135, tm_isdst=-1)
     

   • utcfromtimestamp(self, timestamp) return UTC datetime from a POSIX timestamp.

     >>> datetime.utcfromtimestamp(1494834531.324)
     datetime.datetime(2017, 5, 15, 7, 48, 43, 100000)
     

   • utcnow(cls) return a new datetime representing UTC day and time.

     >>> datetime.utcnow()
     datetime.datetime(2017, 5, 15, 7, 50, 8, 171000)
     

   • utctimetuple(self) return UTC time tuple.

     >>> datetime.utcnow().utctimetuple()
     time.struct_time(tm_year=2017, tm_mon=5, tm_mday=15, tm_hour=7, tm_min=50, tm_sec=44, tm_wday=0, tm_yday=135, tm_isdst=0)
     

4. time模块
   导入time模块: import time

   • asctime(p_tuple=None) convert a time tuple to a string, when the time tuple not present, current times as return by localtime().

     >>> time.asctime()
     'Mon May 15 16:13:52 2017'
     
     >>> time.asctime(datetime.now().timetuple())
     'Mon May 15 16:12:21 2017'
     

   • clock() return the CPU time or real time since the start of the process or since the first call to clock(). This has as much precision as the system records.

     >>> time.clock()
     1102.1906228205012
     

   • ctime(seconds=None) convert a time in seconds since Epoch to a string in local time.

     >>> time.ctime()
     'Mon May 15 16:20:44 2017'
     

   • gmtime(seconds=None) convert seconds since the Epoch to a time tuple expressing UTC.when seconds is not passed in, convert the current time instead.

     >>> time.gmtime()
     time.struct_time(tm_year=2017, tm_mon=5, tm_mday=15, tm_hour=8, tm_min=24, tm_sec=3, tm_wday=0, tm_yday=135, tm_isdst=0)
     

   • localtime(seconds=None) convert seconds since the Epoch to a time tuple expressing local time. where seconds is not passed in, convert the current time instead.

     >>> time.localtime()
     time.struct_time(tm_year=2017, tm_mon=5, tm_mday=15, tm_hour=16, tm_min=26, tm_sec=28, tm_wday=0, tm_yday=135, tm_isdst=0)
     

   • mktime(p_tuple) convert a time tuple in local time to seconds since the Epoch.

     >>> time.mktime(time.localtime())
     1494836918.0
     
     >>> time.mktime(time.gmtime())
     1494808126.0
     

   • sleep(seconds) delay execution for a given number of seconds

     >>> time.sleep(1)
     

   • strftime(format, p_tuple=None) convert a time tuple to a string according to a format specification.when the time tuple is not present, current time as returned by localtime() is used.

     >>> time.strftime("%Y-%m-%d %H:%M:%S")
     '2017-05-15 16:34:20'
     
     >>> time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())
     '2017-05-15 16:34:35'
     

   • strptime(string, format) parse a string to a time tuple according to a format specification.

     >>> time.strptime("2017-05-15 15:20:12", "%Y-%m-%d %H:%M:%S")
     time.struct_time(tm_year=2017, tm_mon=5, tm_mday=15, tm_hour=15, tm_min=20, tm_sec=12, tm_wday=0, tm_yday=135, tm_isdst=-1)
     

   • time() return the current time in seconds since the Epoch.

     >>> time.time()
     1494837455.418
     

5. timedelta类
   表示时间间隔，即两个时间点之间的长度.时间相加减得到timedelta对象. timedelta对象可以与datetime对象相加减得到的是datetime对象.

   • datetime.timedelta(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0, hours=0, weeks=0) 构造函数.
   • 获取相对当前时间,前一天的日期.

     >>> datetime.now() + timedelta(days=-1)
     datetime.datetime(2017, 5, 14, 17, 7, 25, 303000)
     
     >>> datetime.now() - timedelta(days=1)
     datetime.datetime(2017, 5, 14, 17, 7, 41, 430000)
     

   • 计算两个时间,相差的秒数.

     >>> (datetime(2017, 5, 15, 15, 15, 15) - datetime(2017, 5, 15, 16, 16, 16)).total_seconds()
     -3661.0
     

6. calendar模块
   导入calendar模块: import calendar, calendar是第三方库, 使用前需要安装pip install calendar

   • isleap(year) return True for leap year, False for non-leap year.

     >>> calendar.isleap(2017)
     False
     >>> calendar.isleap(2020)
     True
     

   • leapdays(y1, y2) return number of leap years in range[y1, y2). assume y1 <= y2

     >>> calendar.leapdays(2017, 2021)
     1
     

   • weekday(year, month, day) return weekday(0-6 ~ Mon-Sun)

     >>> calendar.weekday(2017, 5, 15)
     0
     

   • monthrange(year, month) return weekday(0-6 ~ Mon-Sun) and number of days(28-31)

     >>> calendar.monthrange(2017, 5)
     (0, 31)