Using the property_exists Function
The property_exists() function will evaluate to see if the specified property exists. It returns a value of TRUE if the property is found and FALSE if not.
demo.php
<?php
include_once("class1.php");
$myObj = new class1();
if(property_exists($myObj, "age")){
echo $myObj->age;
}
?>
class1.php
<?php
class class1 {
public $age = 72;
}
?>