PHP：使用==和比较对象===

Posted 2021-02-26

Here are a few examples that show how the relationship between objects and references

<?php
 
class Box{
	public $name = "box";
}
 
$box = new Box();
$box_reference = $box;
$box_clone = clone $box;
 
$box_changed = clone $box;
$box_changed->name = "changed box";
 
$another_box = new Box();
 
// Attributes are pretty much the same
echo $box == $box_reference ? 'true' : 'false'; 
echo "<br />";
echo $box == $box_clone ? 'true' : 'false'; 
echo "<br />";
echo $box == $box_changed ? 'true' : 'false'; 
echo "<br />";
echo $box == $another_box ? 'true' : 'false'; 
echo "<br />";
echo "<br />";
// Checks to see if they reference the same object
echo $box === $box_reference ? 'true' : 'false'; 
echo "<br />";
echo $box === $box_clone ? 'true' : 'false'; 
echo "<br />";
echo $box === $box_changed ? 'true' : 'false'; 
echo "<br />";
echo $box === $another_box ? 'true' : 'false'; 
echo "<br />";
 
?>