I discovered that a DateTime object in PHP can be compared to another as the ">" and "<" operators are overloaded.
Is it the same with DateInterval?
As I was trying to answer this question, I found something strange:
<?php
$today = new DateTime();
$release = new DateTime('14-02-2012');
$building_time = new DateInterval('P15D');
var_dump($today->diff($release));
var_dump($building_time);
var_dump($today->diff($release)>$building_time);
var_dump($today->diff($release)<$building_time);
if($today->diff($release) < $building_time){
echo 'oK';
}else{
echo 'Just a test';
}
It always echoes "Just a test". The var_dump outputs are:
object(DateInterval)#4 (8) {
["y"]=>
int(0)
["m"]=>
int(0)
["d"]=>
int(18)
["h"]=>
int(16)
["i"]=>
int(49)
["s"]=>
int(19)
["invert"]=>
int(1)
["days"]=>
int(18)
}
object(DateInterval)#3 (8) {
["y"]=>
int(0)
["m"]=>
int(0)
["d"]=>
int(15)
["h"]=>
int(0)
["i"]=>
int(0)
["s"]=>
int(0)
["invert"]=>
int(0)
["days"]=>
bool(false)
}
bool(false)
bool(true)
When I try with a DateTime as "01-03-2012" everything works.
In short, comparing of DateInterval
objects is not currently supported by default (as of php 5.6).
As you already know, the DateTime
Objects are comparable.
A way to achieve the desired result, is to subtract or add the DateInterval
from a DateTime
object and compare the two to determine the difference.
Example: https://3v4l.org/kjJPg
$buildDate = new DateTime('2012-02-15');
$releaseDate = clone $buildDate;
$releaseDate->setDate(2012, 2, 14);
$buildDate->add(new DateInterval('P15D'));
var_dump($releaseDate < $buildDate); //bool(true)
Edit
As of the release of PHP 7.1 the results are different than with PHP 5.x, due to the added support for microseconds.
Example: https://3v4l.org/rCigC
$a = new \DateTime;
$b = new \DateTime;
var_dump($a < $b);
Results (7.1+):
bool(true)
Results (5.x - 7.0.x, 7.1.3):
bool(false)
To circumvent this behavior, it is recommended that you use clone
to compare the DateTime
objects instead.
Example: https://3v4l.org/CSpV8
$a = new \DateTime;
$b = clone $a;
var_dump($a < $b);
Results (5.x - 7.x):
bool(false)