Working with DateTime in projects again have a problem with duplicating if use array_unique to array which have a elemts of object,(but probles only with DateTime), see code:
class simpleClass
{
public $dt;
function __construct($dt)
{
$this->dt = $dt;
}
}
$dateObj = new simpleClass(new DateTime);
$std = new stdClass;
$arr = [$dateObj, $dateObj, $std, $std, $std, $std];
var_dump(array_unique($arr, SORT_REGULAR));
Expected 1 element with dateObj But actually there 2
Function array_unique() will compare strings, so objects will be casted to strings. Solution to that would be to use __toString() magic method to return full date identifier:
class simpleClass
{
public $dt;
function __construct(DateTime $dt) {
$this->dt = $dt;
}
public function __toString() {
return $this->dt->format('r');
}
}
$dateObj1 = new simpleClass(new DateTime);
$dateObj2 = new simpleClass(new DateTime);
$dateObj3 = new simpleClass(new DateTime('today'));
$arr = [$dateObj1, $dateObj2, $dateObj3];
print_r(array_unique($arr));
Demo.
$dateObj or $std to string, it will throw Catchable fatal error: Object of class CLASSNAME could not be converted to string, but when you use them in function array_unique(), where internal cast to string is performed, no error appears and output is strange...array_unique() works with strings. Two elements are considered equal if and only if (string)$elem1===(string)$elem2. In words: when the string representation is the same. The first element will be used. You are casting objects to strings, that don't have toString magic method, so this is the big error.I still can't understand. Setting the array with:
$arr = [$dateObj, $dateObj, $std, $std];
returns:
array (size=2)
0 =>
object(simpleClass)[1]
public 'dt' =>
object(DateTime)[2]
public 'date' => string '2013-11-14 14:37:08' (length=19)
public 'timezone_type' => int 3
public 'timezone' => string 'Europe/Rome' (length=11)
2 =>
object(stdClass)[3]
This way, array_unique seems to work...
