Correction on the previous comment :
Bug fixed in php 7.0.17 and 7.1.3, for the version 7.0.0 to 7.0.16 and 7.1.0 to 7.1.2, the bug is still present
(PHP 5 >= 5.2.0, PHP 7)
DateTime::setDate -- date_date_set — 设置 DateTime 对象的日期
面向对象风格
过程化风格
设置 DateTime 对象的日期。
object仅过程化风格：由 date_create() 返回的 DateTime 类型的对象。此函数会修改这个对象。
year年份。
month月份。
day日。
返回被修改的 DateTime 对象， 或者在失败时返回 FALSE.
| 版本 | 说明 |
|---|---|
| 5.3.0 | 将返回值从NULL改为 DateTime 类型。 |
Example #1 DateTime::setDate() 例程
面向对象风格
<?php
$date = new DateTime();
$date->setDate(2001, 2, 3);
echo $date->format('Y-m-d');
?>
过程化风格
<?php
$date = date_create();
date_date_set($date, 2001, 2, 3);
echo date_format($date, 'Y-m-d');
?>
以上例程会输出：
2001-02-03
Example #2 超出范围的部分会向上一级增加
<?php
$date = new DateTime();
$date->setDate(2001, 2, 28);
echo $date->format('Y-m-d') . "\n";
$date->setDate(2001, 2, 29);
echo $date->format('Y-m-d') . "\n";
$date->setDate(2001, 14, 3);
echo $date->format('Y-m-d') . "\n";
?>
以上例程会输出：
2001-02-28 2001-03-01 2002-02-03
Correction on the previous comment :
Bug fixed in php 7.0.17 and 7.1.3, for the version 7.0.0 to 7.0.16 and 7.1.0 to 7.1.2, the bug is still present
Be carreful about this bug in php 5.6 and lower (fixed in php 7.0 and higher) :
<?php
$date = new DateTime("first day of last month");
echo $date->format('Y-m-d');
echo ' => ' ;
$date->setDate(2013, 2, 3);
echo $date->format('Y-m-d');
?>
Output <=5.6 : 2017-03-01 => 2013-02-01
Output >=7.0 : 2017-03-31 => 2013-02-03
Same goes for "Last day of last month", and the funny part, it will take the last day of the new month setted by setDate
Example with a Leap Year :
<?php
$date = new DateTime("last day of last month");
echo $date->format('Y-m-d');
echo ' => ' ;
$date->setDate(2012, 2, 3);
echo $date->format('Y-m-d');
?>
Output <=5.6 : 2017-03-31 => 2012-02-29
Output >=7.0 : 2017-03-31 => 2012-02-03
Be warned, DateTime::setDate() does not check for invalid input.
Illustration:
<?php
$dt = new DateTime();
$dt->setDate(2012, 11, 31); // returns DateTime object and not false although this date does not exist
echo $dt->format('Y-m-d'); // output: 2012-12-01
?>
No error was generated on entering a non existing date, php silently changed it.