(PHP 5 >= 5.1.0, PHP 7, PHP 8)
property_exists — Checks if the object or class has a property
   This function checks if the given property exists in
   the specified class.
  
Note:
As opposed with isset(), property_exists() returns
trueeven if the property has the valuenull.
object_or_classThe class name or an object of the class to test for
propertyThe name of the property
Example #1 A property_exists() example
<?php
class myClass {
    public $mine;
    private $xpto;
    static protected $test;
    static function test() {
        var_dump(property_exists('myClass', 'xpto')); //true
    }
}
var_dump(property_exists('myClass', 'mine'));   //true
var_dump(property_exists(new myClass, 'mine')); //true
var_dump(property_exists('myClass', 'xpto'));   //true
var_dump(property_exists('myClass', 'bar'));    //false
var_dump(property_exists('myClass', 'test'));   //true
myClass::test();
?>Note:
Using this function will use any registered autoloaders if the class is not already known.
Note:
The property_exists() function cannot detect properties that are magically accessible using the
__getmagic method.