Whenever an object is treated as a string, the __toString() method is called. This method should return a string representation of the class.
class User {
public $first_name;
public $last_name;
public $age;
public function __toString() {
return "{$this->first_name} {$this->last_name} ($this->age)";
}
}
$user = new User();
$user->first_name = "Chuck";
$user->last_name = "Norris";
$user->age = 76;
// Anytime the $user object is used in a string context, __toString() is called
echo $user; // prints 'Chuck Norris (76)'
// String value becomes: 'Selected user: Chuck Norris (76)'
$selected_user_string = sprintf("Selected user: %s", $user);
// Casting to string also calls __toString()
$user_as_string = (string) $user;