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
DateTime::setDate
date_date_set
(PHP 5 >= 5.2.0, PHP 7, PHP 8)
DateTime::setDate -- date_date_set — 设置日期
说明
面向对象风格
过程化风格
将 DateTime 对象的当前日期重置为其它日期。
跟 DateTimeImmutable::setDate() 一样，但适用于 DateTime，且更改现有对象。
过程化版本将 DateTime 对象作为第一个参数。
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
返回方法链修改后的 DateTime 对象。
参见
- DateTimeImmutable::setDate() - Sets the date
add a note
User Contributed Notes 3 notes
kevin dot nadin at gmail dot com ¶
7 years ago
remy215 at laposte dot net ¶
12 years ago
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.
kevin dot nadin at gmail dot com ¶
7 years ago
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
