This article brings you an introduction to the datetime module in Python (with examples). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
Python provides multiple built-in modules for manipulating date and time, such as calendar, time, and datetime. The interface provided by the time module is basically consistent with the C standard library time.h. Compared with the time module, the interface of the datetime module is more intuitive and easier to call.
The module defines two constants:
datetime.MINYEAR
datetime.MAXYEAR
These two constants respectively represent the minimum and maximum year that datetime can represent. Among them, MINYEAR = 1, MAXYEAR = 9999.
datetime The module defines the following classes:
datetime.date: Class representing date. Commonly used attributes include year, month, day;
datetime.time: a class representing time. Commonly used attributes include hour, minute, second, microsecond;
datetime.datetime: represents date and time.
datetime.timedelta: Indicates the time interval, that is, the length between two time points.
datetime.tzinfo: Relevant information related to time zones.
Note: The types of objects listed above are all immutable.
date class represents a date (composed of year, month, and day), and its prototype is as follows:
class datetime.date( year, month, day)
Parameter description:
The range of year is [MINYEAR, MAXYEAR], that is, [1, 9999];
The range of month is [1, 12]. (The month starts from 1, not from 0); The maximum value of
day is determined according to the given year and month parameters. For example, February in a leap year has 29 days; the
date. max, date.min: the maximum and minimum date that the date object can represent;
date.resolution: date object The smallest unit representing a date. Here is the sky.
date.today(): Returns a date object representing the current local date;
date .fromtimestamp(timestamp): Return a date object based on the given time stamp;
datetime.fromordinal(ordinal): Return the Gregorian calendar time Convert to a date object; (Gregorian Calendar: a calendar representation method, similar to our country's lunar calendar, which is more commonly used in Western countries, and will not be discussed in detail here.)
Usage examples: Instance methods and properties provided by
>>> datetime.date.max datetime.date(9999, 12, 31) >>> datetime.date.min datetime.date(1, 1, 1) >>> datetime.date.resolution datetime.timedelta(1) >>> datetime.date.today() datetime.date(2016, 5, 12) >>> datetime.date.fromtimestamp(time.time()) datetime.date(2016, 5, 12)
##date.year, date.month, date.day: Year, month, day;
date.replace(year, month, day): Generate a new date object, use The year, month, and day specified by the parameters replace the attributes in the original object. (The original object remains unchanged)
date.timetuple(): Returns the time.struct_time object corresponding to the date;
date.toordinal(): Returns the Gregorian Calendar date corresponding to the date;
date.weekday(): Returns weekday , if it is Monday, return 0; if it is Tuesday, return 1, and so on;
data.isoweekday(): Return weekday, if On Monday, 1 is returned; if it is Tuesday, 2 is returned, and so on;
date.isocalendar(): The return format is such as (year, month, day) tuple;
date.isoformat(): Returns a string in the format of 'YYYY-MM-DD';
date.strftime(fmt): Custom format string.
>>> today = datetime.date.today()
>>> today.year
2016
>>> today.month
5
>>> today.day
12
>>> tomorrow = today.replace(day=13)
>>> tomorrow
datetime.date(2016, 5, 13)
>>> tomorrow.timetuple()
time.struct_time(tm_year=2016, tm_mon=5, tm_mday=13, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=4, tm_yday=134, tm_isdst=-1)
>>> tomorrow.toordinal()
736097
>>> tomorrow.weekday()
4
>>> tomorrow.isoweekday()
5
>>> tomorrow.isocalendar()
(2016, 19, 5)
>>> tomorrow.isoformat()
'2016-05-13'
>>> tomorrow.strftime("%y-%m-%d")
'16-05-13'
date2 = date1 timedelta：
date2 = date1 - timedelta：
timedelta = date1 - date2：
date1 < date2：
>>> now = datetime.date.today() >>> now datetime.date(2016, 5, 12) >>> now += datetime.date.resolution >>> now datetime.date(2016, 5, 13) >>> now -= datetime.date.resolution >>> now datetime.date(2016, 5, 12) >>> now < datetime.date.max True
time class represents time (composed of hours, minutes, seconds and microseconds), and its prototype is as follows ：
hour 的范围为[0, 24),
minute 的范围为[0, 60)，
second 的范围为[0, 60)，
microsecond 的范围为[0, 1000000),
tzinfo 表示时区信息。
time.min、time.max：time类所能表示的最小、最大时间。其中，time.min = time(0, 0, 0, 0)， time.max = time(23, 59, 59, 999999)；
time.resolution：时间的最小单位，这里是1微秒；
使用示例：
>>> datetime.time.min
datetime.time(0, 0)
>>> datetime.time.max
datetime.time(23, 59, 59, 999999)
>>> datetime.time.resolution
datetime.timedelta(0, 0, 1)</p>
<h4>time类提供的实例方法和属性：</h4>
<ul class=" list-paddingleft-2">
<li><p><strong>time.hour</strong>、<strong>time.minute</strong>、<strong>time.second</strong>、<strong>time.microsecond</strong>：时、分、秒、微秒；</p></li>
<li><p><strong>time.tzinfo</strong>：时区信息；</p></li>
<li><p><strong>time.replace</strong>([hour[, minute[, second[, microsecond[, tzinfo]]]]])：创建一个新的时间对象，用参数指定的时、分、秒、微秒代替原有对象中的属性（原有对象仍保持不变）；</p></li>
<li><p><strong>time.isoformat()</strong>：返回型如"HH:MM:SS"格式的字符串表示；</p></li>
<li><p><strong>time.strftime(fmt)</strong>：返回自定义格式化字符串。</p></li>
</ul>
<p>使用示例：</p>
<pre class="brush:php;toolbar:false">>>> tm = datetime.time(18, 18, 18)
>>> tm.hour
18
>>> tm.minute
18
>>> tm.second
18
>>> tm.microsecond
0
>>> tm.tzinfo
>>> tm.isoformat()
'18:18:18'
>>> tm.replace(hour=20)
datetime.time(20, 18, 18)
>>> tm.strftime("%I:%M:%S %p")
'06:18:18 PM'time 类的对象只能进行比较，无法进行加减操作。
datetime 是 date 与 time 的结合体，包括 date 与 time 的所有信息。其原型如下：
class datetime.datetime(year, month, day, hour=0, minute=0, second=0, microsecond=0, tzinfo=None)
各参数的含义与date、time的构造函数中的一样，要注意参数值的范围。
datetime.min、datetime.max：datetime所能表示的最小值与最大值；
datetime.resolution：datetime最小单位；
datetime.today()：返回一个表示当前本地时间的datetime对象；
datetime.now([tz])：返回一个表示当前本地时间的datetime对象，如果提供了参数tz，则获取tz参数所指时区的本地时间；
datetime.utcnow()：返回一个当前utc时间的datetime对象；
datetime.fromtimestamp(timestamp[, tz])：根据时间戮创建一个datetime对象，参数tz指定时区信息；
datetime.utcfromtimestamp(timestamp)：根据时间戮创建一个datetime对象；
datetime.combine(date, time)：根据date和time，创建一个datetime对象；
datetime.strptime(date_string, format)：将格式字符串转换为datetime对象，data 与 time 类没有提供该方法。
使用示例：
>>> datetime.datetime.min
datetime.datetime(1, 1, 1, 0, 0)
>>> datetime.datetime.max
datetime.datetime(9999, 12, 31, 23, 59, 59, 999999)
>>> datetime.datetime.resolution
datetime.timedelta(0, 0, 1)
>>> print datetime.datetime.resolution
0:00:00.000001
>>> today = datetime.datetime.today()
>>> today
datetime.datetime(2016, 5, 12, 12, 46, 47, 246240)
>>> datetime.datetime.now()
datetime.datetime(2016, 5, 12, 12, 47, 9, 850643)
>>> datetime.datetime.utcnow()
datetime.datetime(2016, 5, 12, 4, 47, 42, 188124)
>>> datetime.datetime.fromtimestamp(time.time())
datetime.datetime(2016, 5, 12, 12, 48, 40, 459676)
>>> datetime.datetime.combine(datetime.date(1990, 10, 05), datetime.time(18, 18, 18))
datetime.datetime(1990, 10, 5, 18, 18, 18)
>>> datetime.datetime.strptime("2010-04-07 01:48:16.234000", "%Y-%m-%d %H:%M:%S .%f")
datetime.datetime(2010, 4, 7, 1, 48, 16, 234000)datetime类提供的实例方法与属性大部分功能与 date 和 time 类似，这里仅罗列方法名不再赘述：
datetime.year、month、day、hour、minute、second、microsecond、tzinfo：
datetime.date()：获取date对象；
datetime.time()：获取time对象；
datetime.replace([year[, month[, day[, hour[, minute[, second[, microsecond[, tzinfo]]]]]]]])：
*datetime.timetuple() *
*datetime.utctimetuple() *
datetime.toordinal()
datetime.weekday()
datetime.isocalendar()
datetime.isoformat([sep])
datetime.ctime()：返回一个日期时间的C格式字符串，等效于time.ctime(time.mktime(dt.timetuple()))；
datetime.strftime(format)
datetime 对象同样可以进行比较，或者相减返回一个时间间隔对象，或者日期时间加上一个间隔返回一个新的日期时间对象。
datetime.timedelta 对象代表两个时间之间的的时间差，两个 date 或 datetime 对象相减时可以返回一个timedelta 对象。其原型如下：
class datetime.timedelta(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0, hours=0, weeks=0)
所有参数可选，且默认都是0，参数的值可以是整数，浮点数，正数或负数。
内部只存储days，seconds，microseconds，其他参数的值会自动按如下规则抓转换：
1 millisecond（毫秒） 转换成 1000 microseconds（微秒）
1 minute 转换成 60 seconds
1 hour 转换成 3600 seconds
1 week转换成 7 days
三个参数的取值范围分别为：
0 <= microseconds < 1000000
0 <= seconds < 3600*24 (the number of seconds in one day)
-999999999 <= days <= 999999999
timedelta.min：时间间隔对象的最小值,即 timedelta(-999999999).
timedelta.max：时间间隔对象的最大值，即 timedelta(days=999999999, hours=23, minutes=59, seconds=59, microseconds=999999).
timedelta.resolution：时间间隔的最小单位,即 timedelta(microseconds=1).
使用示例：
>>> datetime.timedelta.min datetime.timedelta(-999999999) >>> datetime.timedelta.max datetime.timedelta(999999999, 86399, 999999) >>> datetime.timedelta.resolution datetime.timedelta(0, 0, 1) >>> print datetime.timedelta.resolution 0:00:00.000001</p> <h4>timedelta 实例方法</h4> <ul class=" list-paddingleft-2"><li><p><strong>timedelta.total_seconds()</strong>：计算时间间隔的总秒数</p></li></ul> <p>使用示例：</p> <pre class="brush:php;toolbar:false">>>> datetime.timedelta.resolution.total_seconds() 1e-06
datetime、date、time 都提供了 strftime() 方法，该方法接收一个格式字符串，输出日期时间的字符串表示。支持的转换格式如下：
%a星期的简写。如 星期三为Web %A星期的全写。如 星期三为Wednesday %b月份的简写。如4月份为Apr %B月份的全写。如4月份为April %c: 日期时间的字符串表示。（如： 04/07/10 10:43:39） %d: 日在这个月中的天数（是这个月的第几天） %f: 微秒（范围[0,999999]） %H: 小时（24小时制，[0, 23]） %I: 小时（12小时制，[0, 11]） %j: 日在年中的天数 [001,366]（是当年的第几天） %m: 月份（[01,12]） %M: 分钟（[00,59]） %p: AM或者PM %S: 秒（范围为[00,61]，为什么不是[00, 59]，参考python手册~_~） %U: 周在当年的周数当年的第几周），星期天作为周的第一天 %w: 今天在这周的天数，范围为[0, 6]，6表示星期天 %W: 周在当年的周数（是当年的第几周），星期一作为周的第一天 %x: 日期字符串（如：04/07/10） %X: 时间字符串（如：10:43:39） %y: 2个数字表示的年份 %Y: 4个数字表示的年份 %z: 与utc时间的间隔 （如果是本地时间，返回空字符串） %Z: 时区名称（如果是本地时间，返回空字符串） %%: %% => %
使用示例：
>>> dt = datetime.datetime.now()
>>> dt.strftime('%Y-%m-%d %H:%M:%S %f')
'2016-05-12 14:19:22 333943'
>>> dt.strftime('%y-%m-%d %I:%M:%S %p')
'16-05-12 02:19:22 PM'
>>> dt.strftime("%a")
'Thu'
>>> dt.strftime("%A")
'Thursday'
>>> dt.strftime("%b")
'May'
>>> dt.strftime("%B")
'May'
>>> dt.strftime("%c")
'Thu May 12 14:19:22 2016'
>>> dt.strftime("%x")
'05/12/16'
>>> dt.strftime("%X")
'14:19:22'
>>> dt.strftime("%w")
'4'
>>> dt.strftime("%j")
'133'
>>> dt.strftime("%u")
'4'
>>> dt.strftime("%U")
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