PHP get_​class_​vars() Function

What is PHP get_​class_​vars() Function?

If you want to get all the properties (variables) of a class, use PHP get_class_vars() function. The function let you know the name as well as the value of each variable.

Syntax:

get_class_vars(class_name)

Parameters:

The Function has 1 parameter which is required-

class_name (Required): It specifies a string which is a class name. (Check example 1). You can use the get_class() function to get the class name from an object too (Check example 2).

Return Values:

The function returns an associative array whose keys are variable names and their values are the values of the variables.

Examples:

Example 1:

<pre>
<?php
    class Human {
        public $hand = 2;
        public $leg = 2;
        public $finger = 20;
   }
   $var_names = get_class_vars('Human');
   echo "The class 'Human' has the following variables- <br />";
   print_r($var_names);
?>
</pre>

Output:

The class 'Human' has the following variables- 
Array
(
    [hand] => 2
    [leg] => 2
    [finger] => 20
)

Example 2:

<pre>
<?php
   class Human {
      public $hand = 2;
      public $leg = 2;
      public $finger = 20;
   }
   $objHuman = new Human();
   $var_names = get_class_vars(get_class($objHuman));
   echo "The class 'Human' has the following variables- <br />";
   print_r($var_names);
?>
</pre>

Output:

The class 'Human' has the following variables- 
Array
(
    [hand] => 2
    [leg] => 2
    [finger] => 20
)

Notes on get_class_vars() Function:

• This function only returns public variables. So, private and protected variables are not included. Check following example-

<pre>
<?php
   class Human {
      public $hand = 2;
      private $legs = 2;
      protected $tail = "No";
      public $eye = 2;
   }
   $variable_names = get_class_vars('Human');
   echo "The class 'Human' has the following variables- <br />";
   print_r($variable_names);
?>
</pre>

Output:

The class 'Human' has the following variables- 
Array
(
    [hand] => 2
    [eye] => 2
)

• The function returns the default values of the variables. It ignores those values that are applied during object instantiation (ex. constructor __construct) (check 1^st example) or new values from the object instances (check 2^nd example).
• 1^st Example:

<pre>
<?php
    class Human {
        function __construct(){
            $this -> hand = 4;
        }
        public $hand = 2;
        public $leg = 2;
        public $finger = 20;
   }
   $var_names = get_class_vars('Human');
   echo "The class 'Human' has the following variables- <br />";
   print_r($var_names);
?>
</pre>

Output:

The class 'Human' has the following variables- 
Array
(
    [hand] => 2
    [leg] => 2
    [finger] => 20
)

• 2^nd Example:

<pre>
<?php
    class Human {
        public $hand = 2;
        public $leg = 2;
        public $finger = 20;
   }
   $objHuman = new Human();
   $objHuman-> hand = 3;
   $var_names = get_class_vars('Human');
   echo "The class 'Human' has the following variables- <br />";
   print_r($var_names);
?>
</pre>

Output:

The class 'Human' has the following variables- 
Array
(
    [hand] => 2
    [leg] => 2
    [finger] => 20
)

• The function not only displays the variables from itself but also from its parent classes too. Check the following example-

<pre>
<?php
   class Human {
      public $hand = 2;
      public $leg = 2;
   }

   class Male extends Human {
      public $finger = 20;
   }
   $vars_names = get_class_vars('Male');
   print_r($vars_names);
?>
</pre>

Output:

Array
(
    [finger] => 20
    [hand] => 2
    [leg] => 2
)

• If you call the function inside a class, it also displays the private and protected variables beside public variables. Check the following example-

<pre>
<?php
class Human {
      function __construct(){
         echo "The class 'Human' has the following variables- <br />";
         print_r(get_class_vars('Human'));
      }
      public $hand = 2;
      private $legs = 2;
      protected $tail = "No";
      public $eye = 2;
   }
   $objHuman = new Human();
?>
</pre>

Output:

The class 'Human' has the following variables- 
Array
(
    [hand] => 2
    [legs] => 2
    [tail] => No
    [eye] => 2
)

PHP Version Support:

PHP 4, PHP 5, PHP 7, PHP 8

Summary: PHP get_​class_​vars() Function

get_class_vars() is a class/object type function in PHP. It is a useful function to see the list of variables a class contains.

Reference:

https://www.php.net/manual/en/function.get-class-vars.php