DateTime::setDate()

date_date_set

(PHP 5 >= 5.2.0, PHP 7)

设置 DateTime 对象的日期

说明

面向对象风格
publicDateTime::setDate(int $year,int $month,int $day): DateTime

过程化风格
date_date_set(DateTime$object,int $year,int $month,int $day): DateTime

设置 DateTime 对象的日期。

参数

$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。

返回值

返回被修改的 DateTime 对象，或者在失败时返回FALSE.

更新日志

范例

Example #1DateTime::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

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

参见

• DateTime::setISODate() 设置 ISO 日期
• DateTime::setTime() 设置 DateTime 对象的时间

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.

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