8.1. datetime — Basic date and time types

8.1.1. Available Types

class datetime. date

An idealized naive date, assuming the current Gregorian calendar always was, and always will be, in effect. Attributes: year, month, and day.

class datetime. time

An idealized time, independent of any particular day, assuming that every day has exactly 24*60*60 seconds (there is no notion of “leap seconds” here). Attributes: hour, minute, second, microsecond, and tzinfo.

class datetime. datetime

A combination of a date and a time. Attributes: year, month, day, hour, minute, second, microsecond, and tzinfo.

class datetime. timedelta

A duration expressing the difference between two date, time, or datetime instances to microsecond resolution.

class datetime. tzinfo

An abstract base class for time zone information objects. These are used by the datetime and time classes to provide a customizable notion of time adjustment (for example, to account for time zone and/or daylight saving time).

Objects of these types are immutable.

Objects of the date type are always naive.

An object of type time or datetime may be naive or aware. A datetime object d is aware if d.tzinfo is not None and d.tzinfo.utcoffset(d) does not return None. If d.tzinfo is None, or if d.tzinfo is not None but d.tzinfo.utcoffset(d) returns None, d is naive. A time object t is aware if t.tzinfo is not None and t.tzinfo.utcoffset(None) does not return None. Otherwise, t is naive.

The distinction between naive and aware doesn’t apply to timedelta objects.

Subclass relationships:

object
    timedelta
    tzinfo
    time
    date
        datetime

8.1.2. timedelta Objects

A timedelta object represents a duration, the difference between two dates or times.

class datetime. timedelta ( [ days [, seconds [, microseconds [, milliseconds [, minutes [, hours [, weeks ] ] ] ] ] ] ] )

All arguments are optional and default to 0. Arguments may be ints, longs, or floats, and may be positive or negative.

Only days, seconds and microseconds are stored internally. Arguments are converted to those units:

• A millisecond is converted to 1000 microseconds.

• A minute is converted to 60 seconds.

• An hour is converted to 3600 seconds.

• A week is converted to 7 days.

and days, seconds and microseconds are then normalized so that the representation is unique, with

• 0 <= microseconds < 1000000

• 0 <= seconds < 3600*24 (the number of seconds in one day)

• -999999999 <= days <= 999999999

If any argument is a float and there are fractional microseconds, the fractional microseconds left over from all arguments are combined and their sum is rounded to the nearest microsecond. If no argument is a float, the conversion and normalization processes are exact (no information is lost).

If the normalized value of days lies outside the indicated range, OverflowError is raised.

Note that normalization of negative values may be surprising at first. For example,

>>> from datetime import timedelta
>>> d = timedelta(microseconds=-1)
>>> (d.days, d.seconds, d.microseconds)
(-1, 86399, 999999)

Class attributes are:

timedelta. min

The most negative timedelta object, timedelta(-999999999).

timedelta. max

The most positive timedelta object, timedelta(days=999999999, hours=23, minutes=59, seconds=59, microseconds=999999).

timedelta. resolution

The smallest possible difference between non-equal timedelta objects, timedelta(microseconds=1).

Note that, because of normalization, timedelta.max > -timedelta.min. -timedelta.max is not representable as a timedelta object.

Instance attributes (read-only):

Supported operations:

Notes:

1. This is exact, but may overflow.

2. This is exact, and cannot overflow.

3. Division by 0 raises ZeroDivisionError.

4. -timedelta.max is not representable as a timedelta object.

5. String representations of timedelta objects are normalized similarly to their internal representation. This leads to somewhat unusual results for negative timedeltas. For example:

   >>> timedelta(hours=-5)
   datetime.timedelta(-1, 68400)
   >>> print(_)
   -1 day, 19:00:00
   

In addition to the operations listed above timedelta objects support certain additions and subtractions with date and datetime objects (see below).

Comparisons of timedelta objects are supported with the timedelta object representing the smaller duration considered to be the smaller timedelta. In order to stop mixed-type comparisons from falling back to the default comparison by object address, when a timedelta object is compared to an object of a different type, TypeError is raised unless the comparison is == or !=. The latter cases return False or True, respectively.

timedelta objects are hashable (usable as dictionary keys), support efficient pickling, and in Boolean contexts, a timedelta object is considered to be true if and only if it isn’t equal to timedelta(0).

Instance methods:

timedelta. total_seconds ( )

Return the total number of seconds contained in the duration. Equivalent to (td.microseconds + (td.seconds + td.days * 24 * 3600) * 10**6) / 10**6 computed with true division enabled.

Note that for very large time intervals (greater than 270 years on most platforms) this method will lose microsecond accuracy.

New in version 2.7.

Example usage:

>>> from datetime import timedelta
>>> year = timedelta(days=365)
>>> another_year = timedelta(weeks=40, days=84, hours=23,
...                          minutes=50, seconds=600)  # adds up to 365 days
>>> year.total_seconds()
31536000.0
>>> year == another_year
True
>>> ten_years = 10 * year
>>> ten_years, ten_years.days // 365
(datetime.timedelta(3650), 10)
>>> nine_years = ten_years - year
>>> nine_years, nine_years.days // 365
(datetime.timedelta(3285), 9)
>>> three_years = nine_years // 3;
>>> three_years, three_years.days // 365
(datetime.timedelta(1095), 3)
>>> abs(three_years - ten_years) == 2 * three_years + year
True

8.1.3. date Objects

A date object represents a date (year, month and day) in an idealized calendar, the current Gregorian calendar indefinitely extended in both directions. January 1 of year 1 is called day number 1, January 2 of year 1 is called day number 2, and so on. This matches the definition of the “proleptic Gregorian” calendar in Dershowitz and Reingold’s book Calendrical Calculations, where it’s the base calendar for all computations. See the book for algorithms for converting between proleptic Gregorian ordinals and many other calendar systems.

class datetime. date ( year, month, day )

All arguments are required. Arguments may be ints or longs, in the following ranges:

• MINYEAR <= year <= MAXYEAR

• 1 <= month <= 12

• 1 <= day <= number of days in the given month and year

If an argument outside those ranges is given, ValueError is raised.

Other constructors, all class methods:

classmethod date. today ( )

Return the current local date. This is equivalent to date.fromtimestamp(time.time()).

classmethod date. fromtimestamp ( timestamp )

Return the local date corresponding to the POSIX timestamp, such as is returned by time.time(). This may raise ValueError, if the timestamp is out of the range of values supported by the platform C localtime() function. It’s common for this to be restricted to years from 1970 through 2038. Note that on non-POSIX systems that include leap seconds in their notion of a timestamp, leap seconds are ignored by fromtimestamp().

classmethod date. fromordinal ( ordinal )

Return the date corresponding to the proleptic Gregorian ordinal, where January 1 of year 1 has ordinal 1. ValueError is raised unless 1 <= ordinal <= date.max.toordinal(). For any date d, date.fromordinal(d.toordinal()) == d.

Class attributes:

date. min

The earliest representable date, date(MINYEAR, 1, 1).

date. max

The latest representable date, date(MAXYEAR, 12, 31).

date. resolution

The smallest possible difference between non-equal date objects, timedelta(days=1).

Instance attributes (read-only):

date. year

Between MINYEAR and MAXYEAR inclusive.

date. month

Between 1 and 12 inclusive.

date. day

Between 1 and the number of days in the given month of the given year.

Supported operations:

Notes:

1. date2 is moved forward in time if timedelta.days > 0, or backward if timedelta.days < 0. Afterward date2 - date1 == timedelta.days. timedelta.seconds and timedelta.microseconds are ignored. OverflowError is raised if date2.year would be smaller than MINYEAR or larger than MAXYEAR.

2. This isn’t quite equivalent to date1 + (-timedelta), because -timedelta in isolation can overflow in cases where date1 - timedelta does not. timedelta.seconds and timedelta.microseconds are ignored.

3. This is exact, and cannot overflow. timedelta.seconds and timedelta.microseconds are 0, and date2 + timedelta == date1 after.

4. In other words, date1 < date2 if and only if date1.toordinal() < date2.toordinal(). In order to stop comparison from falling back to the default scheme of comparing object addresses, date comparison normally raises TypeError if the other comparand isn’t also a date object. However, NotImplemented is returned instead if the other comparand has a timetuple() attribute. This hook gives other kinds of date objects a chance at implementing mixed-type comparison. If not, when a date object is compared to an object of a different type, TypeError is raised unless the comparison is == or !=. The latter cases return False or True, respectively.

Dates can be used as dictionary keys. In Boolean contexts, all date objects are considered to be true.

Instance methods:

date. replace ( year, month, day )

Return a date with the same value, except for those parameters given new values by whichever keyword arguments are specified. For example, if d == date(2002, 12, 31), then d.replace(day=26) == date(2002, 12, 26).

date. timetuple ( )

Return a time.struct_time such as returned by time.localtime(). The hours, minutes and seconds are 0, and the DST flag is -1. d.timetuple() is equivalent to time.struct_time((d.year, d.month, d.day, 0, 0, 0, d.weekday(), yday, -1)), where yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1 is the day number within the current year starting with 1 for January 1st.

date. toordinal ( )

Return the proleptic Gregorian ordinal of the date, where January 1 of year 1 has ordinal 1. For any date object d, date.fromordinal(d.toordinal()) == d.

date. weekday ( )

Return the day of the week as an integer, where Monday is 0 and Sunday is 6. For example, date(2002, 12, 4).weekday() == 2, a Wednesday. See also isoweekday().

date. isoweekday ( )

Return the day of the week as an integer, where Monday is 1 and Sunday is 7. For example, date(2002, 12, 4).isoweekday() == 3, a Wednesday. See also weekday(), isocalendar().

date. isocalendar ( )

Return a 3-tuple, (ISO year, ISO week number, ISO weekday).

The ISO calendar is a widely used variant of the Gregorian calendar. See https://www.staff.science.uu.nl/~gent0113/calendar/isocalendar.htm for a good explanation.

The ISO year consists of 52 or 53 full weeks, and where a week starts on a Monday and ends on a Sunday. The first week of an ISO year is the first (Gregorian) calendar week of a year containing a Thursday. This is called week number 1, and the ISO year of that Thursday is the same as its Gregorian year.

For example, 2004 begins on a Thursday, so the first week of ISO year 2004 begins on Monday, 29 Dec 2003 and ends on Sunday, 4 Jan 2004, so that date(2003, 12, 29).isocalendar() == (2004, 1, 1) and date(2004, 1, 4).isocalendar() == (2004, 1, 7).

date. isoformat ( )

Return a string representing the date in ISO 8601 format, ‘YYYY-MM-DD’. For example, date(2002, 12, 4).isoformat() == '2002-12-04'.

date. __str__ ( )

For a date d, str(d) is equivalent to d.isoformat().

date. ctime ( )

Return a string representing the date, for example date(2002, 12, 4).ctime() == 'Wed Dec 4 00:00:00 2002'. d.ctime() is equivalent to time.ctime(time.mktime(d.timetuple())) on platforms where the native C ctime() function (which time.ctime() invokes, but which date.ctime() does not invoke) conforms to the C standard.

date. strftime ( format )

Return a string representing the date, controlled by an explicit format string. Format codes referring to hours, minutes or seconds will see 0 values. For a complete list of formatting directives, see section strftime() and strptime() Behavior.

date. __format__ ( format )

Same as date.strftime(). This makes it possible to specify a format string for a date object when using str.format(). See section strftime() and strptime() Behavior.

Example of counting days to an event:

>>> import time
>>> from datetime import date
>>> today = date.today()
>>> today
datetime.date(2007, 12, 5)
>>> today == date.fromtimestamp(time.time())
True
>>> my_birthday = date(today.year, 6, 24)
>>> if my_birthday < today:
...     my_birthday = my_birthday.replace(year=today.year + 1)
>>> my_birthday
datetime.date(2008, 6, 24)
>>> time_to_birthday = abs(my_birthday - today)
>>> time_to_birthday.days
202

Example of working with date:

>>> from datetime import date
>>> d = date.fromordinal(730920) # 730920th day after 1. 1. 0001
>>> d
datetime.date(2002, 3, 11)
>>> t = d.timetuple()
>>> for i in t:     
...     print i
2002                # year
3                   # month
11                  # day
0
0
0
0                   # weekday (0 = Monday)
70                  # 70th day in the year
-1
>>> ic = d.isocalendar()
>>> for i in ic:    
...     print i
2002                # ISO year
11                  # ISO week number
1                   # ISO day number ( 1 = Monday )
>>> d.isoformat()
'2002-03-11'
>>> d.strftime("%d/%m/%y")
'11/03/02'
>>> d.strftime("%A %d. %B %Y")
'Monday 11. March 2002'
>>> 'The {1} is {0:%d}, the {2} is {0:%B}.'.format(d, "day", "month")
'The day is 11, the month is March.'

8.1.4. datetime Objects

A datetime object is a single object containing all the information from a date object and a time object. Like a date object, datetime assumes the current Gregorian calendar extended in both directions; like a time object, datetime assumes there are exactly 3600*24 seconds in every day.

Constructor:

class datetime. datetime ( year, month, day [, hour [, minute [, second [, microsecond [, tzinfo ] ] ] ] ] )

The year, month and day arguments are required. tzinfo may be None, or an instance of a tzinfo subclass. The remaining arguments may be ints or longs, in the following ranges:

• MINYEAR <= year <= MAXYEAR

• 1 <= month <= 12

• 1 <= day <= number of days in the given month and year

• 0 <= hour < 24

• 0 <= minute < 60

• 0 <= second < 60

• 0 <= microsecond < 1000000

If an argument outside those ranges is given, ValueError is raised.

Other constructors, all class methods:

classmethod datetime. today ( )

Return the current local datetime, with tzinfo None. This is equivalent to datetime.fromtimestamp(time.time()). See also now(), fromtimestamp().

classmethod datetime. now ( [ tz ] )

Return the current local date and time. If optional argument tz is None or not specified, this is like today(), but, if possible, supplies more precision than can be gotten from going through a time.time() timestamp (for example, this may be possible on platforms supplying the C gettimeofday() function).

If tz is not None, it must be an instance of a tzinfo subclass, and the current date and time are converted to tz’s time zone. In this case the result is equivalent to tz.fromutc(datetime.utcnow().replace(tzinfo=tz)). See also today(), utcnow().

classmethod datetime. utcnow ( )

Return the current UTC date and time, with tzinfo None. This is like now(), but returns the current UTC date and time, as a naive datetime object. See also now().

classmethod datetime. fromtimestamp ( timestamp [, tz ] )

Return the local date and time corresponding to the POSIX timestamp, such as is returned by time.time(). If optional argument tz is None or not specified, the timestamp is converted to the platform’s local date and time, and the returned datetime object is naive.

If tz is not None, it must be an instance of a tzinfo subclass, and the timestamp is converted to tz’s time zone. In this case the result is equivalent to tz.fromutc(datetime.utcfromtimestamp(timestamp).replace(tzinfo=tz)).

fromtimestamp() may raise ValueError, if the timestamp is out of the range of values supported by the platform C localtime() or gmtime() functions. It’s common for this to be restricted to years in 1970 through 2038. Note that on non-POSIX systems that include leap seconds in their notion of a timestamp, leap seconds are ignored by fromtimestamp(), and then it’s possible to have two timestamps differing by a second that yield identical datetime objects. See also utcfromtimestamp().

classmethod datetime. utcfromtimestamp ( timestamp )

Return the UTC datetime corresponding to the POSIX timestamp, with tzinfo None. This may raise ValueError, if the timestamp is out of the range of values supported by the platform C gmtime() function. It’s common for this to be restricted to years in 1970 through 2038. See also fromtimestamp().

classmethod datetime. fromordinal ( ordinal )

Return the datetime corresponding to the proleptic Gregorian ordinal, where January 1 of year 1 has ordinal 1. ValueError is raised unless 1 <= ordinal <= datetime.max.toordinal(). The hour, minute, second and microsecond of the result are all 0, and tzinfo is None.

classmethod datetime. combine ( date, time )

Return a new datetime object whose date components are equal to the given date object’s, and whose time components and tzinfo attributes are equal to the given time object’s. For any datetime object d, d == datetime.combine(d.date(), d.timetz()). If date is a datetime object, its time components and tzinfo attributes are ignored.

classmethod datetime. strptime ( date_string, format )

Return a datetime corresponding to date_string, parsed according to format. This is equivalent to datetime(*(time.strptime(date_string, format)[0:6])). ValueError is raised if the date_string and format can’t be parsed by time.strptime() or if it returns a value which isn’t a time tuple. For a complete list of formatting directives, see section strftime() and strptime() Behavior.

New in version 2.5.

Class attributes:

datetime. min

The earliest representable datetime, datetime(MINYEAR, 1, 1, tzinfo=None).

datetime. max

The latest representable datetime, datetime(MAXYEAR, 12, 31, 23, 59, 59, 999999, tzinfo=None).

datetime. resolution

The smallest possible difference between non-equal datetime objects, timedelta(microseconds=1).

Instance attributes (read-only):

datetime. year

Between MINYEAR and MAXYEAR inclusive.

datetime. month

Between 1 and 12 inclusive.

datetime. day

Between 1 and the number of days in the given month of the given year.

datetime. hour

In range(24).

datetime. minute

In range(60).

datetime. second

In range(60).

datetime. microsecond

In range(1000000).

datetime. tzinfo

The object passed as the tzinfo argument to the datetime constructor, or None if none was passed.

Supported operations:

1. datetime2 is a duration of timedelta removed from datetime1, moving forward in time if timedelta.days > 0, or backward if timedelta.days < 0. The result has the same tzinfo attribute as the input datetime, and datetime2 - datetime1 == timedelta after. OverflowError is raised if datetime2.year would be smaller than MINYEAR or larger than MAXYEAR. Note that no time zone adjustments are done even if the input is an aware object.

2. Computes the datetime2 such that datetime2 + timedelta == datetime1. As for addition, the result has the same tzinfo attribute as the input datetime, and no time zone adjustments are done even if the input is aware. This isn’t quite equivalent to datetime1 + (-timedelta), because -timedelta in isolation can overflow in cases where datetime1 - timedelta does not.

3. Subtraction of a datetime from a datetime is defined only if both operands are naive, or if both are aware. If one is aware and the other is naive, TypeError is raised.

   If both are naive, or both are aware and have the same tzinfo attribute, the tzinfo attributes are ignored, and the result is a timedelta object t such that datetime2 + t == datetime1. No time zone adjustments are done in this case.

   If both are aware and have different tzinfo attributes, a-b acts as if a and b were first converted to naive UTC datetimes first. The result is (a.replace(tzinfo=None) - a.utcoffset()) - (b.replace(tzinfo=None) - b.utcoffset()) except that the implementation never overflows.

4. datetime1 is considered less than datetime2 when datetime1 precedes datetime2 in time.

   If one comparand is naive and the other is aware, TypeError is raised. If both comparands are aware, and have the same tzinfo attribute, the common tzinfo attribute is ignored and the base datetimes are compared. If both comparands are aware and have different tzinfo attributes, the comparands are first adjusted by subtracting their UTC offsets (obtained from self.utcoffset()).

   Note

   In order to stop comparison from falling back to the default scheme of comparing object addresses, datetime comparison normally raises TypeError if the other comparand isn’t also a datetime object. However, NotImplemented is returned instead if the other comparand has a timetuple() attribute. This hook gives other kinds of date objects a chance at implementing mixed-type comparison. If not, when a datetime object is compared to an object of a different type, TypeError is raised unless the comparison is == or !=. The latter cases return False or True, respectively.

datetime objects can be used as dictionary keys. In Boolean contexts, all datetime objects are considered to be true.

Instance methods:

datetime. date ( )

Return date object with same year, month and day.

datetime. time ( )

Return time object with same hour, minute, second and microsecond. tzinfo is None. See also method timetz().

datetime. timetz ( )

Return time object with same hour, minute, second, microsecond, and tzinfo attributes. See also method time().

datetime. replace ( [ year [, month [, day [, hour [, minute [, second [, microsecond [, tzinfo ] ] ] ] ] ] ] ] )

Return a datetime with the same attributes, except for those attributes given new values by whichever keyword arguments are specified. Note that tzinfo=None can be specified to create a naive datetime from an aware datetime with no conversion of date and time data.

datetime. astimezone ( tz )

Return a datetime object with new tzinfo attribute tz, adjusting the date and time data so the result is the same UTC time as self, but in tz’s local time.

tz must be an instance of a tzinfo subclass, and its utcoffset() and dst() methods must not return None. self must be aware (self.tzinfo must not be None, and self.utcoffset() must not return None).

If self.tzinfo is tz, self.astimezone(tz) is equal to self: no adjustment of date or time data is performed. Else the result is local time in time zone tz, representing the same UTC time as self: after astz = dt.astimezone(tz), astz - astz.utcoffset() will usually have the same date and time data as dt - dt.utcoffset(). The discussion of class tzinfo explains the cases at Daylight Saving Time transition boundaries where this cannot be achieved (an issue only if tz models both standard and daylight time).

If you merely want to attach a time zone object tz to a datetime dt without adjustment of date and time data, use dt.replace(tzinfo=tz). If you merely want to remove the time zone object from an aware datetime dt without conversion of date and time data, use dt.replace(tzinfo=None).

Note that the default tzinfo.fromutc() method can be overridden in a tzinfo subclass to affect the result returned by astimezone(). Ignoring error cases, astimezone() acts like:

def astimezone(self, tz):
    if self.tzinfo is tz:
        return self
    # Convert self to UTC, and attach the new time zone object.
    utc = (self - self.utcoffset()).replace(tzinfo=tz)
    # Convert from UTC to tz's local time.
    return tz.fromutc(utc)

datetime. utcoffset ( )

If tzinfo is None, returns None, else returns self.tzinfo.utcoffset(self), and raises an exception if the latter doesn’t return None, or a timedelta object representing a whole number of minutes with magnitude less than one day.

datetime. dst ( )

If tzinfo is None, returns None, else returns self.tzinfo.dst(self), and raises an exception if the latter doesn’t return None, or a timedelta object representing a whole number of minutes with magnitude less than one day.

datetime. tzname ( )

If tzinfo is None, returns None, else returns self.tzinfo.tzname(self), raises an exception if the latter doesn’t return None or a string object,

datetime. timetuple ( )

Return a time.struct_time such as returned by time.localtime(). d.timetuple() is equivalent to time.struct_time((d.year, d.month, d.day, d.hour, d.minute, d.second, d.weekday(), yday, dst)), where yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1 is the day number within the current year starting with 1 for January 1st. The tm_isdst flag of the result is set according to the dst() method: tzinfo is None or dst() returns None, tm_isdst is set to -1; else if dst() returns a non-zero value, tm_isdst is set to 1; else tm_isdst is set to 0.

datetime. utctimetuple ( )

If datetime instance d is naive, this is the same as d.timetuple() except that tm_isdst is forced to 0 regardless of what d.dst() returns. DST is never in effect for a UTC time.

If d is aware, d is normalized to UTC time, by subtracting d.utcoffset(), and a time.struct_time for the normalized time is returned. tm_isdst is forced to 0. Note that the result’s tm_year member may be MINYEAR-1 or MAXYEAR+1, if d.year was MINYEAR or MAXYEAR and UTC adjustment spills over a year boundary.

datetime. toordinal ( )

Return the proleptic Gregorian ordinal of the date. The same as self.date().toordinal().

datetime. weekday ( )

Return the day of the week as an integer, where Monday is 0 and Sunday is 6. The same as self.date().weekday(). See also isoweekday().

datetime. isoweekday ( )

Return the day of the week as an integer, where Monday is 1 and Sunday is 7. The same as self.date().isoweekday(). See also weekday(), isocalendar().

datetime. isocalendar ( )

Return a 3-tuple, (ISO year, ISO week number, ISO weekday). The same as self.date().isocalendar().

datetime. isoformat ( [ sep ] )

Return a string representing the date and time in ISO 8601 format, YYYY-MM-DDTHH:MM:SS.mmmmmm or, if microsecond is 0, YYYY-MM-DDTHH:MM:SS

If utcoffset() does not return None, a 6-character string is appended, giving the UTC offset in (signed) hours and minutes: YYYY-MM-DDTHH:MM:SS.mmmmmm+HH:MM or, if microsecond is 0 YYYY-MM-DDTHH:MM:SS+HH:MM

The optional argument sep (default 'T') is a one-character separator, placed between the date and time portions of the result. For example,

>>> from datetime import tzinfo, timedelta, datetime
>>> class TZ(tzinfo):
...     def utcoffset(self, dt): return timedelta(minutes=-399)
...
>>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ')
'2002-12-25 00:00:00-06:39'

datetime. __str__ ( )

For a datetime instance d, str(d) is equivalent to d.isoformat(' ').

datetime. ctime ( )

Return a string representing the date and time, for example datetime(2002, 12, 4, 20, 30, 40).ctime() == 'Wed Dec  4 20:30:40 2002'. d.ctime() is equivalent to time.ctime(time.mktime(d.timetuple())) on platforms where the native C ctime() function (which time.ctime() invokes, but which datetime.ctime() does not invoke) conforms to the C standard.

datetime. strftime ( format )

Return a string representing the date and time, controlled by an explicit format string. For a complete list of formatting directives, see section strftime() and strptime() Behavior.

datetime. __format__ ( format )

Same as datetime.strftime(). This makes it possible to specify a format string for a datetime object when using str.format(). See section strftime() and strptime() Behavior.

Examples of working with datetime objects:

>>> from datetime import datetime, date, time
>>> # Using datetime.combine()
>>> d = date(2005, 7, 14)
>>> t = time(12, 30)
>>> datetime.combine(d, t)
datetime.datetime(2005, 7, 14, 12, 30)
>>> # Using datetime.now() or datetime.utcnow()
>>> datetime.now()   
datetime.datetime(2007, 12, 6, 16, 29, 43, 79043)   # GMT +1
>>> datetime.utcnow()   
datetime.datetime(2007, 12, 6, 15, 29, 43, 79060)
>>> # Using datetime.strptime()
>>> dt = datetime.strptime("21/11/06 16:30", "%d/%m/%y %H:%M")
>>> dt
datetime.datetime(2006, 11, 21, 16, 30)
>>> # Using datetime.timetuple() to get tuple of all attributes
>>> tt = dt.timetuple()
>>> for it in tt:   
...     print it
...
2006    # year
11      # month
21      # day
16      # hour
30      # minute
0       # second
1       # weekday (0 = Monday)
325     # number of days since 1st January
-1      # dst - method tzinfo.dst() returned None
>>> # Date in ISO format
>>> ic = dt.isocalendar()
>>> for it in ic:   
...     print it
...
2006    # ISO year
47      # ISO week
2       # ISO weekday
>>> # Formatting datetime
>>> dt.strftime("%A, %d. %B %Y %I:%M%p")
'Tuesday, 21. November 2006 04:30PM'
>>> 'The {1} is {0:%d}, the {2} is {0:%B}, the {3} is {0:%I:%M%p}.'.format(dt, "day", "month", "time")
'The day is 21, the month is November, the time is 04:30PM.'

Using datetime with tzinfo:

>>> from datetime import timedelta, datetime, tzinfo
>>> class GMT1(tzinfo):
...     def utcoffset(self, dt):
...         return timedelta(hours=1) + self.dst(dt)
...     def dst(self, dt):
...         # DST starts last Sunday in March
...         d = datetime(dt.year, 4, 1)   # ends last Sunday in October
...         self.dston = d - timedelta(days=d.weekday() + 1)
...         d = datetime(dt.year, 11, 1)
...         self.dstoff = d - timedelta(days=d.weekday() + 1)
...         if self.dston <=  dt.replace(tzinfo=None) < self.dstoff:
...             return timedelta(hours=1)
...         else:
...             return timedelta(0)
...     def tzname(self,dt):
...          return "GMT +1"
...
>>> class GMT2(tzinfo):
...     def utcoffset(self, dt):
...         return timedelta(hours=2) + self.dst(dt)
...     def dst(self, dt):
...         d = datetime(dt.year, 4, 1)
...         self.dston = d - timedelta(days=d.weekday() + 1)
...         d = datetime(dt.year, 11, 1)
...         self.dstoff = d - timedelta(days=d.weekday() + 1)
...         if self.dston <=  dt.replace(tzinfo=None) < self.dstoff:
...             return timedelta(hours=1)
...         else:
...             return timedelta(0)
...     def tzname(self,dt):
...         return "GMT +2"
...
>>> gmt1 = GMT1()
>>> # Daylight Saving Time
>>> dt1 = datetime(2006, 11, 21, 16, 30, tzinfo=gmt1)
>>> dt1.dst()
datetime.timedelta(0)
>>> dt1.utcoffset()
datetime.timedelta(0, 3600)
>>> dt2 = datetime(2006, 6, 14, 13, 0, tzinfo=gmt1)
>>> dt2.dst()
datetime.timedelta(0, 3600)
>>> dt2.utcoffset()
datetime.timedelta(0, 7200)
>>> # Convert datetime to another time zone
>>> dt3 = dt2.astimezone(GMT2())
>>> dt3     
datetime.datetime(2006, 6, 14, 14, 0, tzinfo=<GMT2 object at 0x...>)
>>> dt2     
datetime.datetime(2006, 6, 14, 13, 0, tzinfo=<GMT1 object at 0x...>)
>>> dt2.utctimetuple() == dt3.utctimetuple()
True

8.1.5. time Objects

A time object represents a (local) time of day, independent of any particular day, and subject to adjustment via a tzinfo object.

class datetime. time ( [ hour [, minute [, second [, microsecond [, tzinfo ] ] ] ] ] )

All arguments are optional. tzinfo may be None, or an instance of a tzinfo subclass. The remaining arguments may be ints or longs, in the following ranges:

• 0 <= hour < 24

• 0 <= minute < 60

• 0 <= second < 60

• 0 <= microsecond < 1000000.

If an argument outside those ranges is given, ValueError is raised. All default to 0 except tzinfo, which defaults to None.

Class attributes:

time. min

The earliest representable time, time(0, 0, 0, 0).

time. max

The latest representable time, time(23, 59, 59, 999999).

time. resolution

The smallest possible difference between non-equal time objects, timedelta(microseconds=1), although note that arithmetic on time objects is not supported.

Instance attributes (read-only):

time. hour

In range(24).

time. minute

In range(60).

time. second

In range(60).

time. microsecond

In range(1000000).

time. tzinfo

The object passed as the tzinfo argument to the time constructor, or None if none was passed.

Supported operations:

• comparison of time to time, where a is considered less than b when a precedes b in time. If one comparand is naive and the other is aware, TypeError is raised. If both comparands are aware, and have the same tzinfo attribute, the common tzinfo attribute is ignored and the base times are compared. If both comparands are aware and have different tzinfo attributes, the comparands are first adjusted by subtracting their UTC offsets (obtained from self.utcoffset()). In order to stop mixed-type comparisons from falling back to the default comparison by object address, when a time object is compared to an object of a different type, TypeError is raised unless the comparison is == or !=. The latter cases return False or True, respectively.

• hash, use as dict key

• efficient pickling

• in Boolean contexts, a time object is considered to be true if and only if, after converting it to minutes and subtracting utcoffset() (or 0 if that’s None), the result is non-zero.

Instance methods:

time. replace ( [ hour [, minute [, second [, microsecond [, tzinfo ] ] ] ] ] )

Return a time with the same value, except for those attributes given new values by whichever keyword arguments are specified. Note that tzinfo=None can be specified to create a naive time from an aware time, without conversion of the time data.

time. isoformat ( )

Return a string representing the time in ISO 8601 format, HH:MM:SS.mmmmmm or, if self.microsecond is 0, HH:MM:SS If utcoffset() does not return None, a 6-character string is appended, giving the UTC offset in (signed) hours and minutes: HH:MM:SS.mmmmmm+HH:MM or, if self.microsecond is 0, HH:MM:SS+HH:MM

time. __str__ ( )

For a time t, str(t) is equivalent to t.isoformat().

time. strftime ( format )

Return a string representing the time, controlled by an explicit format string. For a complete list of formatting directives, see section strftime() and strptime() Behavior.

time. __format__ ( format )

Same as time.strftime(). This makes it possible to specify a format string for a time object when using str.format(). See section strftime() and strptime() Behavior.

time. utcoffset ( )

If tzinfo is None, returns None, else returns self.tzinfo.utcoffset(None), and raises an exception if the latter doesn’t return None or a timedelta object representing a whole number of minutes with magnitude less than one day.

time. dst ( )

If tzinfo is None, returns None, else returns self.tzinfo.dst(None), and raises an exception if the latter doesn’t return None, or a timedelta object representing a whole number of minutes with magnitude less than one day.

time. tzname ( )

If tzinfo is None, returns None, else returns self.tzinfo.tzname(None), or raises an exception if the latter doesn’t return None or a string object.

Example:

>>> from datetime import time, tzinfo, timedelta
>>> class GMT1(tzinfo):
...     def utcoffset(self, dt):
...         return timedelta(hours=1)
...     def dst(self, dt):
...         return timedelta(0)
...     def tzname(self,dt):
...         return "Europe/Prague"
...
>>> t = time(12, 10, 30, tzinfo=GMT1())
>>> t                               
datetime.time(12, 10, 30, tzinfo=<GMT1 object at 0x...>)
>>> gmt = GMT1()
>>> t.isoformat()
'12:10:30+01:00'
>>> t.dst()
datetime.timedelta(0)
>>> t.tzname()
'Europe/Prague'
>>> t.strftime("%H:%M:%S %Z")
'12:10:30 Europe/Prague'
>>> 'The {} is {:%H:%M}.'.format("time", t)
'The time is 12:10.'

8.1.6. tzinfo Objects

class datetime. tzinfo

This is an abstract base class, meaning that this class should not be instantiated directly. You need to derive a concrete subclass, and (at least) supply implementations of the standard tzinfo methods needed by the datetime methods you use. The datetime module does not supply any concrete subclasses of tzinfo.

An instance of (a concrete subclass of) tzinfo can be passed to the constructors for datetime and time objects. The latter objects view their attributes as being in local time, and the tzinfo object supports methods revealing offset of local time from UTC, the name of the time zone, and DST offset, all relative to a date or time object passed to them.

Special requirement for pickling: A tzinfo subclass must have an __init__() method that can be called with no arguments, else it can be pickled but possibly not unpickled again. This is a technical requirement that may be relaxed in the future.

A concrete subclass of tzinfo may need to implement the following methods. Exactly which methods are needed depends on the uses made of aware datetime objects. If in doubt, simply implement all of them.

tzinfo. utcoffset ( self, dt )

Return offset of local time from UTC, in minutes east of UTC. If local time is west of UTC, this should be negative. Note that this is intended to be the total offset from UTC; for example, if a tzinfo object represents both time zone and DST adjustments, utcoffset() should return their sum. If the UTC offset isn’t known, return None. Else the value returned must be a timedelta object specifying a whole number of minutes in the range -1439 to 1439 inclusive (1440 = 24*60; the magnitude of the offset must be less than one day). Most implementations of utcoffset() will probably look like one of these two:

return CONSTANT                 # fixed-offset class
return CONSTANT + self.dst(dt)  # daylight-aware class

If utcoffset() does not return None, dst() should not return None either.

The default implementation of utcoffset() raises NotImplementedError.

tzinfo. dst ( self, dt )

Return the daylight saving time (DST) adjustment, in minutes east of UTC, or None if DST information isn’t known. Return