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DateTime- Encapsulation of date/time values
Module Functions
- Timezones()
-
Return the list of recognized timezone names
Class DateTime
DateTime objects represent instants in time and provide
interfaces for controlling its representation without
affecting the absolute value of the object.
DateTime objects may be created from a wide variety of string
or numeric data, or may be computed from other DateTime objects.
DateTimes support the ability to convert their representations
to many major timezones, as well as the ablility to create a
DateTime object in the context of a given timezone.
DateTime objects provide partial numerical behavior:
Two date-time objects can be subtracted to obtain a time,
in days between the two.
A date-time object and a positive or negative number may
be added to obtain a new date-time object that is the given
number of days later than the input date-time object.
A positive or negative number and a date-time object may
be added to obtain a new date-time object that is the given
number of days later than the input date-time object.
A positive or negative number may be subtracted from a
date-time object to obtain a new date-time object that is
the given number of days earlier than the input date-time
object.
DateTime objects may be converted to integer, long, or float
numbers of days since January 1, 1901, using the standard int,
long, and float functions (Compatibility Note: int, long and
float return the number of days since 1901 in GMT rather than
local machine timezone). DateTime objects also provide access
to their value in a float format usable with the python time
module, provided that the value of the object falls in the
range of the epoch-based time module.
A DateTime object should be considered immutable; all conversion
and numeric operations return a new DateTime object rather than
modify the current object.
Constructor For DateTime -
- DateTime()
-
Return a new date-time object
A DateTime object always maintains its value as an absolute
UTC time, and is represented in the context of some timezone
based on the arguments used to create the object. A DateTime
object's methods return values based on the timezone context.
Note that in all cases the local machine timezone is used for
representation if no timezone is specified.
DateTimes may be created with from zero to seven arguments.
If the function is called with no arguments, then the
current date/time is returned, represented in the
timezone of the local machine.
If the function is invoked with a single string argument
which is a recognized timezone name, an object representing
the current time is returned, represented in the specified
timezone.
If the function is invoked with a single string argument
representing a valid date/time, an object representing
that date/time will be returned.
As a general rule, any date-time representation that is
recognized and unambigous to a resident of North America is
acceptable.(The reason for this qualification is that
in North America, a date like: 2/1/1994 is interpreted
as February 1, 1994, while in some parts of the world,
it is interpreted as January 2, 1994.) A date/time
string consists of two components, a date component and
an optional time component, separated by one or more
spaces. If the time component is omited, 12:00am is
assumed. Any recognized timezone name specified as the
final element of the date/time string will be used for
computing the date/time value. (If you create a DateTime
with the string Mar 9, 1997 1:45pm US/Pacific , the
value will essentially be the same as if you had captured
time.time() at the specified date and time on a machine in
that timezone)
e=DateTime(US/Eastern )
# returns current date/time, represented in US/Eastern.
x=DateTime(1997/3/9 1:45pm )
# returns specified time, represented in local machine zone.
y=DateTime(Mar 9, 1997 13:45:00 )
# y is equal to x
The date component consists of year, month, and day
values. The year value must be a one-, two-, or
four-digit integer. If a one- or two-digit year is
used, the year is assumed to be in the twentieth
century. The month may an integer, from 1 to 12, a
month name, or a month abreviation, where a period may
optionally follow the abreviation. The day must be an
integer from 1 to the number of days in the month. The
year, month, and day values may be separated by
periods, hyphens, forward, shashes, or spaces. Extra
spaces are permitted around the delimiters. Year,
month, and day values may be given in any order as long
as it is possible to distinguish the components. If all
three components are numbers that are less than 13,
then a a month-day-year ordering is assumed.
The time component consists of hour, minute, and second
values separated by colons. The hour value must be an
integer between 0 and 23 inclusively. The minute value
must be an integer between 0 and 59 inclusively. The
second value may be an integer value between 0 and
59.999 inclusively. The second value or both the minute
and second values may be ommitted. The time may be
followed by am or pm in upper or lower case, in which
case a 12-hour clock is assumed.
If the DateTime function is invoked with a single
Numeric argument, the number is assumed to be either
a floating point value such as that returned by
time.time() , or a number of days after January 1, 1901
00:00:00 UTC.
A DateTime object is returned that represents either
the gmt value of the time.time() float represented in
the local machine's timezone, or that number of days
after January 1, 1901. Note that the number of days
after 1901 need to be expressed from the viewpoint of
the local machine's timezone. A negative argument will
yield a date-time value before 1901.
If the function is invoked with two numeric arguments,
then the first is taken to be an integer year and the
second argument is taken to be an offset in days from
the beginning of the year, in the context of the local
machine timezone.
The date-time value returned is the given offset number of
days from the beginning of the given year, represented in
the timezone of the local machine. The offset may be positive
or negative.
Two-digit years are assumed to be in the twentieth
century.
If the function is invoked with two arguments, the first
a float representing a number of seconds past the epoch
in gmt (such as those returned by time.time()) and the
second a string naming a recognized timezone, a DateTime
with a value of that gmt time will be returned, represented
in the given timezone.
import time
t=time.time()
now_east=DateTime(t,'US/Eastern')
# Time t represented as US/Eastern
now_west=DateTime(t,'US/Pacific')
# Time t represented as US/Pacific
# now_east == now_west
# only their representations are different
If the function is invoked with three or more numeric
arguments, then the first is taken to be an integer
year, the second is taken to be an integer month, and
the third is taken to be an integer day. If the
combination of values is not valid, then a
DateTimeError is raised. Two-digit years are assumed
to be in the twentieth century. The fourth, fifth, and
sixth arguments are floating point, positive or
negative offsets in units of hours, minutes, and days,
and default to zero if not given. An optional string may
be given as the final argument to indicate timezone (the
effect of this is as if you had taken the value of time.time()
at that time on a machine in the specified timezone).
If a string argument passed to the DateTime constructor cannot be
parsed, it will raise DateTime.SyntaxError. Invalid date, time, or
timezone components will raise a DateTime.DateTimeError.
The module function Timezones() will return a list of the
timezones recognized by the DateTime module. Recognition of
timezone names is case-insensitive.
Instance Methods For DateTime -
- aMonth()
-
Return the abreviated month name.
- pCommon()
-
Return a string representing the object's value
in the format: Mar. 1, 1997 1:45 pm
- minute()
-
Return the minute
- isLeapYear()
-
Return true if the current year (in the context of the object's
timezone) is a leap year
- pMonth()
-
Return the abreviated (with period) month name.
- DayOfWeek()
-
Compatibility: see Day
- Day_()
-
Compatibility: see pDay
- isCurrentDay()
-
Return true if this object represents a date/time
that falls within the current day, in the context
of this object's timezone representation
- Mon()
-
Compatibility: see aMonth
- hour()
-
Return the 24-hour clock representation of the hour
- Date()
-
Return the date string for the object.
- aCommonZ()
-
Return a string representing the object's value
in the format: Mar 1, 1997 1:45 pm US/Eastern
- fCommonZ()
-
Return a string representing the object's value
in the format: March 1, 1997 1:45 pm US/Eastern
- isCurrentYear()
-
Return true if this object represents a date/time
that falls within the current year, in the context
of this object's timezone representation
- AMPMMinutes()
-
Return the time string for an object not showing seconds.
- dd()
-
Return day as a 2 digit string
- TimeMinutes()
-
Return the time string for an object not showing seconds.
- h_24()
-
Return the 24-hour clock representation of the hour
- isPast()
-
Return true if this object represents a date/time
earlier than the time of the call
- dow()
-
Return the integer day of the week, where sunday is 0
- isFuture()
-
Return true if this object represents a date/time
later than the time of the call
- pCommonZ()
-
Return a string representing the object's value
in the format: Mar. 1, 1997 1:45 pm US/Eastern
- timezone()
-
Return the timezone in which the object is represented.
- h_12()
-
Return the 12-hour clock representation of the hour
- PreciseTime()
-
Return the time string for the object.
- isCurrentMinute()
-
Return true if this object represents a date/time
that falls within the current minute, in the context
of this object's timezone representation
- rfc822()
-
Return the date in RFC 822 format
- equalTo(t)
-
Compare this DateTime object to another DateTime object
OR a floating point number such as that which is returned
by the python time module. Returns true if the object
represents a date/time equal to the specified DateTime
or time module style time.
- yy()
-
Return calendar year as a 2 digit string
- mm()
-
Return month as a 2 digit string
- Mon_()
-
Compatibility: see pMonth
- toZone(z)
-
Return a DateTime with the value as the current
object, represented in the indicated timezone.
- earliestTime()
-
Return a new DateTime object that represents the earliest
possible time (in whole seconds) that still falls within
the current object's day, in the object's timezone context
- aDay()
-
Return the abreviated name of the day of the week
- dayOfYear()
-
Return the day of the year, in context of
the timezone representation of the object
- latestTime()
-
Return a new DateTime object that represents the latest
possible time (in whole seconds) that still falls within
the current object's day, in the object's timezone context
- notEqualTo(t)
-
Compare this DateTime object to another DateTime object
OR a floating point number such as that which is returned
by the python time module. Returns true if the object
represents a date/time not equal to the specified DateTime
or time module style time.
- PreciseAMPM()
-
Return the time string for the object.
- day()
-
Return the integer day
- timeTime()
-
Return the date/time as a floating-point number in UTC,
in the format used by the python time module.
Note that it is possible to create date/time values
with DateTime that have no meaningful value to the
time module, and in such cases a DateTimeError is
raised. A DateTime object's value must generally be
between Jan 1, 1970 (or your local machine epoch) and
Jan 2038 to produce a valid time.time() style value.
- ampm()
-
Return the appropriate time modifier (am or pm)
- greaterThan(t)
-
Compare this DateTime object to another DateTime object
OR a floating point number such as that which is returned
by the python time module. Returns true if the object
represents a date/time greater than the specified DateTime
or time module style time.
- month()
-
Return the month of the object as an integer
- AMPM()
-
Return the time string for an object to the nearest second.
- second()
-
Return the second
- parts()
-
Return a tuple containing the calendar year, month,
day, hour, minute second and timezone of the object
- greaterThanEqualTo(t)
-
Compare this DateTime object to another DateTime object
OR a floating point number such as that which is returned
by the python time module. Returns true if the object
represents a date/time greater than or equal to the
specified DateTime or time module style time.
- lessThanEqualTo(t)
-
Compare this DateTime object to another DateTime object
OR a floating point number such as that which is returned
by the python time module. Returns true if the object
represents a date/time less than or equal to the specified
DateTime or time module style time.
- isCurrentHour()
-
Return true if this object represents a date/time
that falls within the current hour, in the context
of this object's timezone representation
- aCommon()
-
Return a string representing the object's value
in the format: Mar 1, 1997 1:45 pm
- dow_1()
-
Return the integer day of the week, where sunday is 1
- Day()
-
Return the full name of the day of the week
- fCommon()
-
Return a string representing the object's value
in the format: March 1, 1997 1:45 pm
- Month()
-
Return the full month name
- isCurrentMonth()
-
Return true if this object represents a date/time
that falls within the current month, in the context
of this object's timezone representation
- year()
-
Return the calendar year of the object
- lessThan(t)
-
Compare this DateTime object to another DateTime object
OR a floating point number such as that which is returned
by the python time module. Returns true if the object
represents a date/time less than the specified DateTime
or time module style time.
- Time()
-
Return the time string for an object to the nearest second.
- pDay()
-
Return the abreviated (with period) name of the day of the week
General Services Provided by DateTime -
- `aDateTime`
-
Convert a DateTime to a string that
looks like a Python expression.
- str(aDateTime)
-
Convert a DateTime to a string.
- cmp(aDateTime, other)
-
Compare a DateTime with another DateTime object, or
a float such as those returned by time.time().
NOTE: __cmp__ support is provided for backward
compatibility only, and mixing DateTimes with
ExtensionClasses could cause __cmp__ to break.
You should use the methods lessThan, greaterThan,
lessThanEqualTo, greaterThanEqualTo, equalTo and
notEqualTo to avoid potential problems later!!
- hash(aDateTime)
-
Compute a hash value for a DateTime
Numeric Services Provided by DateTime -
- aDateTime + other
-
A DateTime may be added to a number and a number may be
added to a DateTime; two DateTimes cannot be added.
- aDateTime - other
-
Either a DateTime or a number may be subtracted from a
DateTime, however, a DateTime may not be subtracted from
a number.
- other + aDateTimeAdd aDateTime to other.
-
A DateTime may be added to a number and a number may be
added to a DateTime; two DateTimes cannot be added.
- int(aDateTime)
-
Convert to an integer number of days since Jan. 1, 1901 (gmt)
- long(aDateTime)
-
Convert to a long-int number of days since Jan. 1, 1901 (gmt)
- float(aDateTime)
-
Convert to floating-point number of days since Jan. 1, 1901 (gmt)
Last Modified: 14 March 1997
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