| Date::Simple(3pm) | User Contributed Perl Documentation | Date::Simple(3pm) |
Date::Simple - a simple date object
use Date::Simple ('date', 'today');
# Difference in days between two dates:
$diff = date('2001-08-27') - date('1977-10-05');
# Offset $n days from now:
$date = today() + $n;
print "$date\n"; # uses ISO 8601 format (YYYY-MM-DD)
use Date::Simple ();
my $date = Date::Simple->new('1972-01-17');
my $year = $date->year;
my $month = $date->month;
my $day = $date->day;
use Date::Simple (':all');
my $date2 = ymd($year, $month, $day);
my $date3 = d8('19871218');
my $today = today();
my $tomorrow = $today + 1;
if ($tomorrow->year != $today->year) {
print "Today is New Year's Eve!\n";
}
if ($today > $tomorrow) {
die "warp in space-time continuum";
}
print "Today is ";
print(('Sun','Mon','Tues','Wednes','Thurs','Fri','Satur')
[$today->day_of_week]);
print "day.\n";
# you can also do this:
($date cmp "2001-07-01")
# and this
($date <=> [2001, 7, 1])
Dates are complex enough without times and timezones. This module may be used to create simple date objects. It handles:
It does not deal with hours, minutes, seconds, and time zones.
A date is uniquely identified by year, month, and day integers within valid ranges. This module will not allow the creation of objects for invalid dates. Attempting to create an invalid date will return undef. Month numbering starts at 1 for January, unlike in C and Java. Years are 4-digit.
Gregorian dates up to year 9999 are handled correctly, but we rely on Perl's builtin "localtime" function when the current date is requested. On some platforms, "localtime" may be vulnerable to rollovers such as the Unix "time_t" wraparound of 18 January 2038.
Overloading is used so you can compare or subtract two dates using standard numeric operators such as "==", and the sum of a date object and an integer is another date object.
Date::Simple objects are immutable. After assigning $date1 to $date2, no change to $date1 can affect $date2. This means, for example, that there is nothing like a "set_year" operation, and "$date++" assigns a new object to $date.
This module contains various undocumented functions. They may not be available on all platforms and are likely to change or disappear in future releases. Please let the author know if you think any of them should be public.
As of version 3.0 new ways of controlling the output formats of Date::Simple objects has been provided. However Date::Simple has traditionally provided few ways of stringification, a primary one via the format() method and another primary one via direct stringification. However the later is currently implemented as an XS routine and the former is implemented through a perl routine. This means that using format() is more expensive than stringification and that the stringification format is class specific.
In order to alleviate some of these problems a new mechanism has been introduced to Date::Simple that allows for a per object level format default. In addition a set of utility classes that have different stringification overloads provided. These classes are simple subclasses of Date::Simple and beside the default format() and the overloaded stringification behaviour are identical to Date::Simple. In fact one is totally identical to Date::Simple and is provided mostly for completeness.
The classes included are:
NOTE its important to remember that the primary difference between the behaviour of objects of the different classes is how they are stringified when quoted, and what date format is used by default when the format() method is called. Nothing else differs.
Several functions take a string or numeric representation and generate a corresponding date object. The most general is "new", whose argument list may be empty (returning the current date), a string in format YYYY-MM-DD or YYYYMMDD, a list or arrayref of year, month, and day number, or an existing date object.
my $date = Date::Simple->new('1972-01-17');
The "new" method will return a date object if the values passed in specify a valid date. (See above.) If an invalid date is passed, the method returns undef. If the argument is invalid in form as opposed to numeric range, "new" dies.
The "date" function provides the same functionality but must be imported or qualified as "Date::Simple::date". (To import all public functions, do "use Date::Simple (':all');".) This function returns undef on all invalid input, rather than dying in some cases like "new".
Caution: To get tomorrow's date (or any fixed offset from today), do not use "today + 1". Perl parses this as "today(+1)". You need to put empty parentheses after the function: "today() + 1".
Example:
use Date::Simple ('ymd');
$pbd = ymd(1987, 12, 18);
Example:
use Date::Simple ('d8');
$doi = d8('17760704');
Mnemonic: The string matches "/\d{8}/". Also, "d8" spells "date", if 8 is expanded phonetically.
my $tomorrow = $today->next;
Returns an object representing tomorrow.
my $yesterday = $today->prev;
Returns an object representing yesterday.
my $year = $date->year;
Return the year of DATE as an integer.
my $month = $date->month;
Return the month of DATE as an integer from 1 to 12.
my $day = $date->day;
Return the DATE's day of the month as an integer from 1 to 31.
my ($year, $month, $day) = $date->as_ymd;
Returns a list of three numbers: year, month, and day.
my $change_date = $date->format("%d %b %y");
my $iso_date1 = $date->format("%Y-%m-%d");
my $iso_date2 = $date->format;
The formatting parameter is similar to one you would pass to strftime(3). This is because we actually do pass it to strftime to format the date. This may result in differing behavior across platforms and locales and may not even work everywhere.
Some operators can be used with Date::Simple instances. If one side of an expression is a date object, and the operator expects two date objects, the other side is interpreted as "date(ARG)", so an array reference or ISO 8601 string will work.
Marty Pauley <marty@kasei.com>
John Tobey <jtobey@john-edwin-tobey.org>
Yves Orton <demerphq@hotmail.com>
Copyright (C) 2001 Kasei.
Copyright (C) 2001,2002 John Tobey.
Copyright (C) 2004 Yves Orton.
This program is free software; you can redistribute it and/or
modify it under the terms of either:
a) the GNU General Public License;
either version 2 of the License, or (at your option) any later
version. You should have received a copy of the GNU General
Public License along with this program; see the file COPYING.
If not, write to the Free Software Foundation, Inc., 59
Temple Place, Suite 330, Boston, MA 02111-1307 USA
b) the Perl Artistic License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Date::Simple::Fmt Date::Simple::ISO Date::Simple::D8 and of course perl
| 2022-10-19 | perl v5.36.0 |