jpayne@69: The DateTime package
jpayne@69: ====================
jpayne@69: 
jpayne@69: Encapsulation of date/time values.
jpayne@69: 
jpayne@69: 
jpayne@69: Function Timezones()
jpayne@69: --------------------
jpayne@69: 
jpayne@69: Returns the list of recognized timezone names:
jpayne@69: 
jpayne@69:   >>> from DateTime import Timezones
jpayne@69:   >>> zones = set(Timezones())
jpayne@69: 
jpayne@69: Almost all of the standard pytz timezones are included, with the exception
jpayne@69: of some commonly-used but ambiguous abbreviations, where historical Zope
jpayne@69: usage conflicts with the name used by pytz:
jpayne@69: 
jpayne@69:   >>> import pytz
jpayne@69:   >>> [x for x in pytz.all_timezones if x not in zones]
jpayne@69:   ['CET', 'EET', 'EST', 'MET', 'MST', 'WET']
jpayne@69: 
jpayne@69: Class DateTime
jpayne@69: --------------
jpayne@69: 
jpayne@69: DateTime objects represent instants in time and provide interfaces for
jpayne@69: controlling its representation without affecting the absolute value of
jpayne@69: the object.
jpayne@69: 
jpayne@69: DateTime objects may be created from a wide variety of string or
jpayne@69: numeric data, or may be computed from other DateTime objects.
jpayne@69: DateTimes support the ability to convert their representations to many
jpayne@69: major timezones, as well as the ability to create a DateTime object
jpayne@69: in the context of a given timezone.
jpayne@69: 
jpayne@69: DateTime objects provide partial numerical behavior:
jpayne@69: 
jpayne@69: * Two date-time objects can be subtracted to obtain a time, in days
jpayne@69:   between the two.
jpayne@69: 
jpayne@69: * A date-time object and a positive or negative number may be added to
jpayne@69:   obtain a new date-time object that is the given number of days later
jpayne@69:   than the input date-time object.
jpayne@69: 
jpayne@69: * A positive or negative number and a date-time object may be added to
jpayne@69:   obtain a new date-time object that is the given number of days later
jpayne@69:   than the input date-time object.
jpayne@69: 
jpayne@69: * A positive or negative number may be subtracted from a date-time
jpayne@69:   object to obtain a new date-time object that is the given number of
jpayne@69:   days earlier than the input date-time object.
jpayne@69: 
jpayne@69: DateTime objects may be converted to integer, long, or float numbers
jpayne@69: of days since January 1, 1901, using the standard int, long, and float
jpayne@69: functions (Compatibility Note: int, long and float return the number
jpayne@69: of days since 1901 in GMT rather than local machine timezone).
jpayne@69: DateTime objects also provide access to their value in a float format
jpayne@69: usable with the Python time module, provided that the value of the
jpayne@69: object falls in the range of the epoch-based time module.
jpayne@69: 
jpayne@69: A DateTime object should be considered immutable; all conversion and numeric
jpayne@69: operations return a new DateTime object rather than modify the current object.
jpayne@69: 
jpayne@69: A DateTime object always maintains its value as an absolute UTC time,
jpayne@69: and is represented in the context of some timezone based on the
jpayne@69: arguments used to create the object.  A DateTime object's methods
jpayne@69: return values based on the timezone context.
jpayne@69: 
jpayne@69: Note that in all cases the local machine timezone is used for
jpayne@69: representation if no timezone is specified.
jpayne@69: 
jpayne@69: Constructor for DateTime
jpayne@69: ------------------------
jpayne@69: 
jpayne@69: DateTime() returns a new date-time object.  DateTimes may be created
jpayne@69: with from zero to seven arguments:
jpayne@69: 
jpayne@69: * If the function is called with no arguments, then the current date/
jpayne@69:   time is returned, represented in the timezone of the local machine.
jpayne@69: 
jpayne@69: * If the function is invoked with a single string argument which is a
jpayne@69:   recognized timezone name, an object representing the current time is
jpayne@69:   returned, represented in the specified timezone.
jpayne@69: 
jpayne@69: * If the function is invoked with a single string argument
jpayne@69:   representing a valid date/time, an object representing that date/
jpayne@69:   time will be returned.
jpayne@69: 
jpayne@69:   As a general rule, any date-time representation that is recognized
jpayne@69:   and unambiguous to a resident of North America is acceptable.  (The
jpayne@69:   reason for this qualification is that in North America, a date like:
jpayne@69:   2/1/1994 is interpreted as February 1, 1994, while in some parts of
jpayne@69:   the world, it is interpreted as January 2, 1994.) A date/ time
jpayne@69:   string consists of two components, a date component and an optional
jpayne@69:   time component, separated by one or more spaces.  If the time
jpayne@69:   component is omitted, 12:00am is assumed.
jpayne@69:   
jpayne@69:   Any recognized timezone name specified as the final element of the
jpayne@69:   date/time string will be used for computing the date/time value.
jpayne@69:   (If you create a DateTime with the string,
jpayne@69:   "Mar 9, 1997 1:45pm US/Pacific", the value will essentially be the
jpayne@69:   same as if you had captured time.time() at the specified date and
jpayne@69:   time on a machine in that timezone).  If no timezone is passed, then
jpayne@69:   the timezone configured on the local machine will be used, **except**
jpayne@69:   that if the date format matches ISO 8601 ('YYYY-MM-DD'), the instance
jpayne@69:   will use UTC / GMT+0 as the timezone.
jpayne@69: 
jpayne@69:   o Returns current date/time, represented in US/Eastern:
jpayne@69: 
jpayne@69:     >>> from DateTime import DateTime
jpayne@69:     >>> e = DateTime('US/Eastern')
jpayne@69:     >>> e.timezone()
jpayne@69:     'US/Eastern'
jpayne@69: 
jpayne@69:   o Returns specified time, represented in local machine zone:
jpayne@69: 
jpayne@69:     >>> x = DateTime('1997/3/9 1:45pm')
jpayne@69:     >>> x.parts() # doctest: +ELLIPSIS
jpayne@69:     (1997, 3, 9, 13, 45, ...)
jpayne@69: 
jpayne@69:   o Specified time in local machine zone, verbose format:
jpayne@69: 
jpayne@69:     >>> y = DateTime('Mar 9, 1997 13:45:00')
jpayne@69:     >>> y.parts() # doctest: +ELLIPSIS
jpayne@69:     (1997, 3, 9, 13, 45, ...)
jpayne@69:     >>> y == x
jpayne@69:     True
jpayne@69:     
jpayne@69:   o Specified time in UTC via ISO 8601 rule:
jpayne@69:   
jpayne@69:     >>> z = DateTime('2014-03-24')
jpayne@69:     >>> z.parts() # doctest: +ELLIPSIS
jpayne@69:     (2014, 3, 24, 0, 0, ...)
jpayne@69:     >>> z.timezone()
jpayne@69:     'GMT+0'
jpayne@69: 
jpayne@69:   The date component consists of year, month, and day values.  The
jpayne@69:   year value must be a one-, two-, or four-digit integer.  If a one-
jpayne@69:   or two-digit year is used, the year is assumed to be in the
jpayne@69:   twentieth century.  The month may an integer, from 1 to 12, a month
jpayne@69:   name, or a month abbreviation, where a period may optionally follow
jpayne@69:   the abbreviation.  The day must be an integer from 1 to the number of
jpayne@69:   days in the month.  The year, month, and day values may be separated
jpayne@69:   by periods, hyphens, forward slashes, or spaces.  Extra spaces are
jpayne@69:   permitted around the delimiters.  Year, month, and day values may be
jpayne@69:   given in any order as long as it is possible to distinguish the
jpayne@69:   components.  If all three components are numbers that are less than
jpayne@69:   13, then a month-day-year ordering is assumed.
jpayne@69: 
jpayne@69:   The time component consists of hour, minute, and second values
jpayne@69:   separated by colons.  The hour value must be an integer between 0
jpayne@69:   and 23 inclusively.  The minute value must be an integer between 0
jpayne@69:   and 59 inclusively.  The second value may be an integer value
jpayne@69:   between 0 and 59.999 inclusively.  The second value or both the
jpayne@69:   minute and second values may be omitted.  The time may be followed
jpayne@69:   by am or pm in upper or lower case, in which case a 12-hour clock is
jpayne@69:   assumed.
jpayne@69: 
jpayne@69: * If the DateTime function is invoked with a single numeric argument,
jpayne@69:   the number is assumed to be either a floating point value such as
jpayne@69:   that returned by time.time(), or a number of days after January 1,
jpayne@69:   1901 00:00:00 UTC.
jpayne@69: 
jpayne@69:   A DateTime object is returned that represents either the GMT value
jpayne@69:   of the time.time() float represented in the local machine's
jpayne@69:   timezone, or that number of days after January 1, 1901.  Note that
jpayne@69:   the number of days after 1901 need to be expressed from the
jpayne@69:   viewpoint of the local machine's timezone.  A negative argument will
jpayne@69:   yield a date-time value before 1901.
jpayne@69: 
jpayne@69: * If the function is invoked with two numeric arguments, then the
jpayne@69:   first is taken to be an integer year and the second argument is
jpayne@69:   taken to be an offset in days from the beginning of the year, in the
jpayne@69:   context of the local machine timezone.  The date-time value returned
jpayne@69:   is the given offset number of days from the beginning of the given
jpayne@69:   year, represented in the timezone of the local machine.  The offset
jpayne@69:   may be positive or negative.  Two-digit years are assumed to be in
jpayne@69:   the twentieth century.
jpayne@69: 
jpayne@69: * If the function is invoked with two arguments, the first a float
jpayne@69:   representing a number of seconds past the epoch in GMT (such as
jpayne@69:   those returned by time.time()) and the second a string naming a
jpayne@69:   recognized timezone, a DateTime with a value of that GMT time will
jpayne@69:   be returned, represented in the given timezone.
jpayne@69: 
jpayne@69:     >>> import time
jpayne@69:     >>> t = time.time()
jpayne@69: 
jpayne@69:   Time t represented as US/Eastern:
jpayne@69: 
jpayne@69:     >>> now_east = DateTime(t, 'US/Eastern')
jpayne@69: 
jpayne@69:   Time t represented as US/Pacific:
jpayne@69: 
jpayne@69:     >>> now_west = DateTime(t, 'US/Pacific')
jpayne@69: 
jpayne@69:   Only their representations are different:
jpayne@69: 
jpayne@69:     >>> now_east.equalTo(now_west)
jpayne@69:     True
jpayne@69: 
jpayne@69: * If the function is invoked with three or more numeric arguments,
jpayne@69:   then the first is taken to be an integer year, the second is taken
jpayne@69:   to be an integer month, and the third is taken to be an integer day.
jpayne@69:   If the combination of values is not valid, then a DateTimeError is
jpayne@69:   raised.  One- or two-digit years up to 69 are assumed to be in the 
jpayne@69:   21st century, whereas values 70-99 are assumed to be 20th century.
jpayne@69:   The fourth, fifth, and sixth arguments are floating point, positive
jpayne@69:   or negative offsets in units of hours, minutes, and days, and
jpayne@69:   default to zero if not given.  An optional string may be given as
jpayne@69:   the final argument to indicate timezone (the effect of this is as if
jpayne@69:   you had taken the value of time.time() at that time on a machine in
jpayne@69:   the specified timezone).
jpayne@69: 
jpayne@69: If a string argument passed to the DateTime constructor cannot be
jpayne@69: parsed, it will raise SyntaxError.  Invalid date, time, or
jpayne@69: timezone components will raise a DateTimeError.
jpayne@69: 
jpayne@69: The module function Timezones() will return a list of the timezones
jpayne@69: recognized by the DateTime module.  Recognition of timezone names is
jpayne@69: case-insensitive.
jpayne@69: 
jpayne@69: Instance Methods for DateTime (IDateTime interface)
jpayne@69: ---------------------------------------------------
jpayne@69: 
jpayne@69: Conversion and comparison methods
jpayne@69: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jpayne@69: 
jpayne@69: * ``timeTime()`` returns the date/time as a floating-point number in
jpayne@69:   UTC, in the format used by the Python time module.  Note that it is
jpayne@69:   possible to create date /time values with DateTime that have no
jpayne@69:   meaningful value to the time module, and in such cases a
jpayne@69:   DateTimeError is raised.  A DateTime object's value must generally
jpayne@69:   be between Jan 1, 1970 (or your local machine epoch) and Jan 2038 to
jpayne@69:   produce a valid time.time() style value.
jpayne@69: 
jpayne@69:     >>> dt = DateTime('Mar 9, 1997 13:45:00 US/Eastern')
jpayne@69:     >>> dt.timeTime()
jpayne@69:     857933100.0
jpayne@69: 
jpayne@69:     >>> DateTime('2040/01/01 UTC').timeTime()
jpayne@69:     2208988800.0
jpayne@69: 
jpayne@69:     >>> DateTime('1900/01/01 UTC').timeTime()
jpayne@69:     -2208988800.0
jpayne@69: 
jpayne@69: * ``toZone(z)`` returns a DateTime with the value as the current
jpayne@69:   object, represented in the indicated timezone:
jpayne@69: 
jpayne@69:     >>> dt.toZone('UTC')
jpayne@69:     DateTime('1997/03/09 18:45:00 UTC')
jpayne@69: 
jpayne@69:     >>> dt.toZone('UTC').equalTo(dt)
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``isFuture()`` returns true if this object represents a date/time
jpayne@69:   later than the time of the call:
jpayne@69: 
jpayne@69:     >>> dt.isFuture()
jpayne@69:     False
jpayne@69:     >>> DateTime('Jan 1 3000').isFuture() # not time-machine safe!
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``isPast()`` returns true if this object represents a date/time
jpayne@69:   earlier than the time of the call:
jpayne@69: 
jpayne@69:     >>> dt.isPast()
jpayne@69:     True
jpayne@69:     >>> DateTime('Jan 1 3000').isPast() # not time-machine safe!
jpayne@69:     False
jpayne@69: 
jpayne@69: * ``isCurrentYear()`` returns true if this object represents a
jpayne@69:   date/time that falls within the current year, in the context of this
jpayne@69:   object's timezone representation:
jpayne@69: 
jpayne@69:     >>> dt.isCurrentYear()
jpayne@69:     False
jpayne@69:     >>> DateTime().isCurrentYear()
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``isCurrentMonth()`` returns true if this object represents a
jpayne@69:   date/time that falls within the current month, in the context of
jpayne@69:   this object's timezone representation:
jpayne@69: 
jpayne@69:     >>> dt.isCurrentMonth()
jpayne@69:     False
jpayne@69:     >>> DateTime().isCurrentMonth()
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``isCurrentDay()`` returns true if this object represents a
jpayne@69:   date/time that falls within the current day, in the context of this
jpayne@69:   object's timezone representation:
jpayne@69: 
jpayne@69:     >>> dt.isCurrentDay()
jpayne@69:     False
jpayne@69:     >>> DateTime().isCurrentDay()
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``isCurrentHour()`` returns true if this object represents a
jpayne@69:   date/time that falls within the current hour, in the context of this
jpayne@69:   object's timezone representation:
jpayne@69: 
jpayne@69:     >>> dt.isCurrentHour()
jpayne@69:     False
jpayne@69: 
jpayne@69:     >>> DateTime().isCurrentHour()
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``isCurrentMinute()`` returns true if this object represents a
jpayne@69:   date/time that falls within the current minute, in the context of
jpayne@69:   this object's timezone representation:
jpayne@69: 
jpayne@69:     >>> dt.isCurrentMinute()
jpayne@69:     False
jpayne@69:     >>> DateTime().isCurrentMinute()
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``isLeapYear()`` returns true if the current year (in the context of
jpayne@69:   the object's timezone) is a leap year:
jpayne@69: 
jpayne@69:     >>> dt.isLeapYear()
jpayne@69:     False
jpayne@69:     >>> DateTime('Mar 8 2004').isLeapYear()
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``earliestTime()`` returns a new DateTime object that represents the
jpayne@69:     earliest possible time (in whole seconds) that still falls within
jpayne@69:     the current object's day, in the object's timezone context:
jpayne@69: 
jpayne@69:     >>> dt.earliestTime()
jpayne@69:     DateTime('1997/03/09 00:00:00 US/Eastern')
jpayne@69: 
jpayne@69: * ``latestTime()`` return a new DateTime object that represents the
jpayne@69:   latest possible time (in whole seconds) that still falls within the
jpayne@69:   current object's day, in the object's timezone context
jpayne@69: 
jpayne@69:     >>> dt.latestTime()
jpayne@69:     DateTime('1997/03/09 23:59:59 US/Eastern')
jpayne@69: 
jpayne@69: Component access
jpayne@69: ~~~~~~~~~~~~~~~~
jpayne@69: 
jpayne@69: * ``parts()`` returns a tuple containing the calendar year, month,
jpayne@69:   day, hour, minute second and timezone of the object
jpayne@69: 
jpayne@69:     >>> dt.parts() # doctest: +ELLIPSIS
jpayne@69:     (1997, 3, 9, 13, 45, ... 'US/Eastern')
jpayne@69: 
jpayne@69: * ``timezone()`` returns the timezone in which the object is represented:
jpayne@69: 
jpayne@69:     >>> dt.timezone() in Timezones()
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``tzoffset()`` returns the timezone offset for the objects timezone:
jpayne@69: 
jpayne@69:     >>> dt.tzoffset()
jpayne@69:     -18000
jpayne@69: 
jpayne@69: * ``year()`` returns the calendar year of the object:
jpayne@69: 
jpayne@69:     >>> dt.year()
jpayne@69:     1997
jpayne@69: 
jpayne@69: * ``month()`` returns the month of the object as an integer:
jpayne@69: 
jpayne@69:     >>> dt.month()
jpayne@69:     3
jpayne@69: 
jpayne@69: * ``Month()`` returns the full month name:
jpayne@69: 
jpayne@69:     >>> dt.Month()
jpayne@69:     'March'
jpayne@69: 
jpayne@69: * ``aMonth()`` returns the abbreviated month name:
jpayne@69: 
jpayne@69:     >>> dt.aMonth()
jpayne@69:     'Mar'
jpayne@69: 
jpayne@69: * ``pMonth()`` returns the abbreviated (with period) month name:
jpayne@69: 
jpayne@69:     >>> dt.pMonth()
jpayne@69:     'Mar.'
jpayne@69: 
jpayne@69: * ``day()`` returns the integer day:
jpayne@69: 
jpayne@69:     >>> dt.day()
jpayne@69:     9
jpayne@69: 
jpayne@69: * ``Day()`` returns the full name of the day of the week:
jpayne@69: 
jpayne@69:     >>> dt.Day()
jpayne@69:     'Sunday'
jpayne@69: 
jpayne@69: * ``dayOfYear()`` returns the day of the year, in context of the
jpayne@69:   timezone representation of the object:
jpayne@69: 
jpayne@69:     >>> dt.dayOfYear()
jpayne@69:     68
jpayne@69: 
jpayne@69: * ``aDay()`` returns the abbreviated name of the day of the week:
jpayne@69: 
jpayne@69:     >>> dt.aDay()
jpayne@69:     'Sun'
jpayne@69: 
jpayne@69: * ``pDay()`` returns the abbreviated (with period) name of the day of
jpayne@69:   the week:
jpayne@69: 
jpayne@69:     >>> dt.pDay()
jpayne@69:     'Sun.'
jpayne@69: 
jpayne@69: * ``dow()`` returns the integer day of the week, where Sunday is 0:
jpayne@69: 
jpayne@69:     >>> dt.dow()
jpayne@69:     0
jpayne@69: 
jpayne@69: * ``dow_1()`` returns the integer day of the week, where sunday is 1:
jpayne@69: 
jpayne@69:     >>> dt.dow_1()
jpayne@69:     1
jpayne@69: 
jpayne@69: * ``h_12()`` returns the 12-hour clock representation of the hour:
jpayne@69: 
jpayne@69:     >>> dt.h_12()
jpayne@69:     1
jpayne@69: 
jpayne@69: * ``h_24()`` returns the 24-hour clock representation of the hour:
jpayne@69: 
jpayne@69:     >>> dt.h_24()
jpayne@69:     13
jpayne@69: 
jpayne@69: * ``ampm()`` returns the appropriate time modifier (am or pm):
jpayne@69: 
jpayne@69:     >>> dt.ampm()
jpayne@69:     'pm'
jpayne@69: 
jpayne@69: * ``hour()`` returns the 24-hour clock representation of the hour:
jpayne@69: 
jpayne@69:     >>> dt.hour()
jpayne@69:     13
jpayne@69: 
jpayne@69: * ``minute()`` returns the minute:
jpayne@69: 
jpayne@69:     >>> dt.minute()
jpayne@69:     45
jpayne@69: 
jpayne@69: * ``second()`` returns the second:
jpayne@69: 
jpayne@69:     >>> dt.second() == 0
jpayne@69:     True
jpayne@69: 
jpayne@69: * ``millis()`` returns the milliseconds since the epoch in GMT.
jpayne@69: 
jpayne@69:     >>> dt.millis() == 857933100000
jpayne@69:     True
jpayne@69: 
jpayne@69: strftime()
jpayne@69: ~~~~~~~~~~
jpayne@69: 
jpayne@69: See ``tests/test_datetime.py``.
jpayne@69: 
jpayne@69: General formats from previous DateTime
jpayne@69: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jpayne@69: 
jpayne@69: * ``Date()`` return the date string for the object:
jpayne@69: 
jpayne@69:     >>> dt.Date()
jpayne@69:     '1997/03/09'
jpayne@69: 
jpayne@69: * ``Time()`` returns the time string for an object to the nearest
jpayne@69:   second:
jpayne@69: 
jpayne@69:     >>> dt.Time()
jpayne@69:     '13:45:00'
jpayne@69: 
jpayne@69: * ``TimeMinutes()`` returns the time string for an object not showing
jpayne@69:   seconds:
jpayne@69: 
jpayne@69:     >>> dt.TimeMinutes()
jpayne@69:     '13:45'
jpayne@69: 
jpayne@69: * ``AMPM()`` returns the time string for an object to the nearest second:
jpayne@69: 
jpayne@69:     >>> dt.AMPM()
jpayne@69:     '01:45:00 pm'
jpayne@69: 
jpayne@69: * ``AMPMMinutes()`` returns the time string for an object not showing
jpayne@69:   seconds:
jpayne@69: 
jpayne@69:     >>> dt.AMPMMinutes()
jpayne@69:     '01:45 pm'
jpayne@69: 
jpayne@69: * ``PreciseTime()`` returns the time string for the object:
jpayne@69: 
jpayne@69:     >>> dt.PreciseTime()
jpayne@69:     '13:45:00.000'
jpayne@69: 
jpayne@69: * ``PreciseAMPM()`` returns the time string for the object:
jpayne@69: 
jpayne@69:     >>> dt.PreciseAMPM()
jpayne@69:     '01:45:00.000 pm'
jpayne@69: 
jpayne@69: * ``yy()`` returns the calendar year as a 2 digit string
jpayne@69: 
jpayne@69:     >>> dt.yy()
jpayne@69:     '97'
jpayne@69: 
jpayne@69: * ``mm()`` returns the month as a 2 digit string
jpayne@69: 
jpayne@69:     >>> dt.mm()
jpayne@69:     '03'
jpayne@69: 
jpayne@69: * ``dd()`` returns the day as a 2 digit string:
jpayne@69: 
jpayne@69:     >>> dt.dd()
jpayne@69:     '09'
jpayne@69: 
jpayne@69: * ``rfc822()`` returns the date in RFC 822 format:
jpayne@69: 
jpayne@69:     >>> dt.rfc822()
jpayne@69:     'Sun, 09 Mar 1997 13:45:00 -0500'
jpayne@69: 
jpayne@69: New formats
jpayne@69: ~~~~~~~~~~~
jpayne@69: 
jpayne@69: * ``fCommon()`` returns a string representing the object's value in
jpayne@69:   the format: March 9, 1997 1:45 pm:
jpayne@69: 
jpayne@69:     >>> dt.fCommon()
jpayne@69:     'March 9, 1997 1:45 pm'
jpayne@69: 
jpayne@69: * ``fCommonZ()`` returns a string representing the object's value in
jpayne@69:   the format: March 9, 1997 1:45 pm US/Eastern:
jpayne@69: 
jpayne@69:     >>> dt.fCommonZ()
jpayne@69:     'March 9, 1997 1:45 pm US/Eastern'
jpayne@69: 
jpayne@69: * ``aCommon()`` returns a string representing the object's value in
jpayne@69:   the format: Mar 9, 1997 1:45 pm:
jpayne@69: 
jpayne@69:     >>> dt.aCommon()
jpayne@69:     'Mar 9, 1997 1:45 pm'
jpayne@69: 
jpayne@69: * ``aCommonZ()`` return a string representing the object's value in
jpayne@69:   the format: Mar 9, 1997 1:45 pm US/Eastern:
jpayne@69: 
jpayne@69:     >>> dt.aCommonZ()
jpayne@69:     'Mar 9, 1997 1:45 pm US/Eastern'
jpayne@69: 
jpayne@69: * ``pCommon()`` returns a string representing the object's value in
jpayne@69:   the format Mar. 9, 1997 1:45 pm:
jpayne@69: 
jpayne@69:     >>> dt.pCommon()
jpayne@69:     'Mar. 9, 1997 1:45 pm'
jpayne@69: 
jpayne@69: * ``pCommonZ()`` returns a string representing the object's value in
jpayne@69:   the format: Mar. 9, 1997 1:45 pm US/Eastern:
jpayne@69: 
jpayne@69:     >>> dt.pCommonZ()
jpayne@69:     'Mar. 9, 1997 1:45 pm US/Eastern'
jpayne@69: 
jpayne@69: * ``ISO()`` returns a string with the date/time in ISO format.  Note:
jpayne@69:   this is not ISO 8601-format! See the ISO8601 and HTML4 methods below
jpayne@69:   for ISO 8601-compliant output.  Dates are output as: YYYY-MM-DD HH:MM:SS
jpayne@69: 
jpayne@69:     >>> dt.ISO()
jpayne@69:     '1997-03-09 13:45:00'
jpayne@69: 
jpayne@69: * ``ISO8601()`` returns the object in ISO 8601-compatible format
jpayne@69:   containing the date, time with seconds-precision and the time zone
jpayne@69:   identifier - see http://www.w3.org/TR/NOTE-datetime.  Dates are
jpayne@69:   output as: YYYY-MM-DDTHH:MM:SSTZD (T is a literal character, TZD is
jpayne@69:   Time Zone Designator, format +HH:MM or -HH:MM).
jpayne@69: 
jpayne@69:   The ``HTML4()`` method below offers the same formatting, but
jpayne@69:   converts to UTC before returning the value and sets the TZD"Z"
jpayne@69: 
jpayne@69:     >>> dt.ISO8601()
jpayne@69:     '1997-03-09T13:45:00-05:00'
jpayne@69: 
jpayne@69: 
jpayne@69: * ``HTML4()`` returns the object in the format used in the HTML4.0
jpayne@69:   specification, one of the standard forms in ISO8601.  See
jpayne@69:   http://www.w3.org/TR/NOTE-datetime.  Dates are output as:
jpayne@69:   YYYY-MM-DDTHH:MM:SSZ (T, Z are literal characters, the time is in
jpayne@69:   UTC.):
jpayne@69: 
jpayne@69:     >>> dt.HTML4()
jpayne@69:     '1997-03-09T18:45:00Z'
jpayne@69: 
jpayne@69: * ``JulianDay()`` returns the Julian day according to
jpayne@69:   http://www.tondering.dk/claus/cal/node3.html#sec-calcjd
jpayne@69: 
jpayne@69:     >>> dt.JulianDay()
jpayne@69:     2450517
jpayne@69: 
jpayne@69: * ``week()`` returns the week number according to ISO
jpayne@69:   see http://www.tondering.dk/claus/cal/node6.html#SECTION00670000000000000000
jpayne@69: 
jpayne@69:     >>> dt.week()
jpayne@69:     10
jpayne@69: 
jpayne@69: Deprecated API
jpayne@69: ~~~~~~~~~~~~~~
jpayne@69: 
jpayne@69: * DayOfWeek(): see Day()
jpayne@69: 
jpayne@69: * Day_(): see pDay()
jpayne@69: 
jpayne@69: * Mon(): see aMonth()
jpayne@69: 
jpayne@69: * Mon_(): see pMonth
jpayne@69: 
jpayne@69: General Services Provided by DateTime
jpayne@69: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jpayne@69: 
jpayne@69: DateTimes can be repr()'ed; the result will be a string indicating how
jpayne@69: to make a DateTime object like this:
jpayne@69: 
jpayne@69:   >>> repr(dt)
jpayne@69:   "DateTime('1997/03/09 13:45:00 US/Eastern')"
jpayne@69: 
jpayne@69: When we convert them into a string, we get a nicer string that could
jpayne@69: actually be shown to a user:
jpayne@69: 
jpayne@69:   >>> str(dt)
jpayne@69:   '1997/03/09 13:45:00 US/Eastern'
jpayne@69: 
jpayne@69: The hash value of a DateTime is based on the date and time and is
jpayne@69: equal for different representations of the DateTime:
jpayne@69: 
jpayne@69:   >>> hash(dt)
jpayne@69:   3618678
jpayne@69:   >>> hash(dt.toZone('UTC'))
jpayne@69:   3618678
jpayne@69: 
jpayne@69: DateTime objects can be compared to other DateTime objects OR floating
jpayne@69: point numbers such as the ones which are returned by the Python time
jpayne@69: module by using the equalTo method. Using this API, True is returned if the
jpayne@69: object represents a date/time equal to the specified DateTime or time module
jpayne@69: style time:
jpayne@69: 
jpayne@69:   >>> dt.equalTo(dt)
jpayne@69:   True
jpayne@69:   >>> dt.equalTo(dt.toZone('UTC'))
jpayne@69:   True
jpayne@69:   >>> dt.equalTo(dt.timeTime())
jpayne@69:   True
jpayne@69:   >>> dt.equalTo(DateTime())
jpayne@69:   False
jpayne@69: 
jpayne@69: Same goes for inequalities:
jpayne@69: 
jpayne@69:   >>> dt.notEqualTo(dt)
jpayne@69:   False
jpayne@69:   >>> dt.notEqualTo(dt.toZone('UTC'))
jpayne@69:   False
jpayne@69:   >>> dt.notEqualTo(dt.timeTime())
jpayne@69:   False
jpayne@69:   >>> dt.notEqualTo(DateTime())
jpayne@69:   True
jpayne@69: 
jpayne@69: Normal equality operations only work with DateTime objects and take the
jpayne@69: timezone setting into account:
jpayne@69: 
jpayne@69:   >>> dt == dt
jpayne@69:   True
jpayne@69:   >>> dt == dt.toZone('UTC')
jpayne@69:   False
jpayne@69:   >>> dt == DateTime()
jpayne@69:   False
jpayne@69: 
jpayne@69:   >>> dt != dt
jpayne@69:   False
jpayne@69:   >>> dt != dt.toZone('UTC')
jpayne@69:   True
jpayne@69:   >>> dt != DateTime()
jpayne@69:   True
jpayne@69: 
jpayne@69: But the other comparison operations compare the referenced moment in time and
jpayne@69: not the representation itself:
jpayne@69: 
jpayne@69:   >>> dt > dt
jpayne@69:   False
jpayne@69:   >>> DateTime() > dt
jpayne@69:   True
jpayne@69:   >>> dt > DateTime().timeTime()
jpayne@69:   False
jpayne@69:   >>> DateTime().timeTime() > dt
jpayne@69:   True
jpayne@69: 
jpayne@69:   >>> dt.greaterThan(dt)
jpayne@69:   False
jpayne@69:   >>> DateTime().greaterThan(dt)
jpayne@69:   True
jpayne@69:   >>> dt.greaterThan(DateTime().timeTime())
jpayne@69:   False
jpayne@69: 
jpayne@69:   >>> dt >= dt
jpayne@69:   True
jpayne@69:   >>> DateTime() >= dt
jpayne@69:   True
jpayne@69:   >>> dt >= DateTime().timeTime()
jpayne@69:   False
jpayne@69:   >>> DateTime().timeTime() >= dt
jpayne@69:   True
jpayne@69: 
jpayne@69:   >>> dt.greaterThanEqualTo(dt)
jpayne@69:   True
jpayne@69:   >>> DateTime().greaterThanEqualTo(dt)
jpayne@69:   True
jpayne@69:   >>> dt.greaterThanEqualTo(DateTime().timeTime())
jpayne@69:   False
jpayne@69: 
jpayne@69:   >>> dt < dt
jpayne@69:   False
jpayne@69:   >>> DateTime() < dt
jpayne@69:   False
jpayne@69:   >>> dt < DateTime().timeTime()
jpayne@69:   True
jpayne@69:   >>> DateTime().timeTime() < dt
jpayne@69:   False
jpayne@69: 
jpayne@69:   >>> dt.lessThan(dt)
jpayne@69:   False
jpayne@69:   >>> DateTime().lessThan(dt)
jpayne@69:   False
jpayne@69:   >>> dt.lessThan(DateTime().timeTime())
jpayne@69:   True
jpayne@69: 
jpayne@69:   >>> dt <= dt
jpayne@69:   True
jpayne@69:   >>> DateTime() <= dt
jpayne@69:   False
jpayne@69:   >>> dt <= DateTime().timeTime()
jpayne@69:   True
jpayne@69:   >>> DateTime().timeTime() <= dt
jpayne@69:   False
jpayne@69: 
jpayne@69:   >>> dt.lessThanEqualTo(dt)
jpayne@69:   True
jpayne@69:   >>> DateTime().lessThanEqualTo(dt)
jpayne@69:   False
jpayne@69:   >>> dt.lessThanEqualTo(DateTime().timeTime())
jpayne@69:   True
jpayne@69: 
jpayne@69: Numeric Services Provided by DateTime
jpayne@69: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jpayne@69: 
jpayne@69: A DateTime may be added to a number and a number may be added to a
jpayne@69: DateTime:
jpayne@69: 
jpayne@69:   >>> dt + 5
jpayne@69:   DateTime('1997/03/14 13:45:00 US/Eastern')
jpayne@69:   >>> 5 + dt
jpayne@69:   DateTime('1997/03/14 13:45:00 US/Eastern')
jpayne@69: 
jpayne@69: Two DateTimes cannot be added:
jpayne@69: 
jpayne@69:   >>> from DateTime.interfaces import DateTimeError
jpayne@69:   >>> try:
jpayne@69:   ...     dt + dt
jpayne@69:   ...     print('fail')
jpayne@69:   ... except DateTimeError:
jpayne@69:   ...     print('ok')
jpayne@69:   ok
jpayne@69: 
jpayne@69: Either a DateTime or a number may be subtracted from a DateTime,
jpayne@69: however, a DateTime may not be subtracted from a number:
jpayne@69: 
jpayne@69:   >>> DateTime('1997/03/10 13:45 US/Eastern') - dt
jpayne@69:   1.0
jpayne@69:   >>> dt - 1
jpayne@69:   DateTime('1997/03/08 13:45:00 US/Eastern')
jpayne@69:   >>> 1 - dt
jpayne@69:   Traceback (most recent call last):
jpayne@69:   ...
jpayne@69:   TypeError: unsupported operand type(s) for -: 'int' and 'DateTime'
jpayne@69: 
jpayne@69: DateTimes can also be converted to integers (number of seconds since
jpayne@69: the epoch) and floats:
jpayne@69: 
jpayne@69:   >>> int(dt)
jpayne@69:   857933100
jpayne@69:   >>> float(dt)
jpayne@69:   857933100.0