(PHP 5 >= 5.5.0, PHP 7, PHP 8, PECL >= 3.0.0a1)
IntlCalendar::add — Add a (signed) amount of time to a field
面向对象风格
$field, int $value): bool过程化风格
Add a signed amount to a field. Adding a positive amount allows advances in time, even if the numeric value of the field decreases (e.g. when working with years in BC dates).
Other fields may need to adjusted – for instance, adding a month to the 31st of January will result in the 28th (or 29th) of February. Contrary to IntlCalendar::roll(), when a value wraps around, more significant fields may change. For instance, adding a day to the 31st of January will result in the 1st of February, not the 1st of January.
calendarIntlCalendar 实例。
field
One of the IntlCalendar date/time field constants. These are integer
values between 0 and
IntlCalendar::FIELD_COUNT.
value
The signed amount to add to the current field. If the amount is positive,
the instant will be moved forward; if it is negative, the instant will be
moved into the past. The unit is implicit to the field type. For instance,
hours for IntlCalendar::FIELD_HOUR_OF_DAY.
Returns true on success 或者在失败时返回 false.
示例 #1 IntlCalendar::add()
<?php
ini_set('intl.default_locale', 'fr_FR');
ini_set('date.timezone', 'UTC');
$cal = new IntlGregorianCalendar(2012, 0 /* January */, 31);
echo IntlDateFormatter::formatObject($cal), "\n";
$cal->add(IntlCalendar::FIELD_MONTH, 1);
echo IntlDateFormatter::formatObject($cal), "\n";
$cal->add(IntlCalendar::FIELD_DAY_OF_MONTH, 1);
echo IntlDateFormatter::formatObject($cal), "\n";
以上例程会输出：
31 janv. 2012 00:00:00 29 févr. 2012 00:00:00 1 mars 2012 00:00:00