PHP 7.1.0 Released

property_exists

(PHP 5 >= 5.1.0, PHP 7)

property_exists Checks if the object or class has a property

Description

bool property_exists ( mixed $class , string $property )

This function checks if the given property exists in the specified class.

Note:

As opposed with isset(), property_exists() returns TRUE even if the property has the value NULL.

Parameters

class

The class name or an object of the class to test for

property

The name of the property

Return Values

Returns TRUE if the property exists, FALSE if it doesn't exist or NULL in case of an error.

Notes

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 __get magic method.

Changelog

Version Description
5.3.0 This function checks the existence of a property independent of accessibility.

Examples

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, as of PHP 5.3.0
var_dump(property_exists('myClass''bar'));    //false
var_dump(property_exists('myClass''test'));   //true, as of PHP 5.3.0
myClass::test();

?>

See Also

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User Contributed Notes 6 notes

up
20
g dot gentile at parentesigraffe dot com
1 year ago
The function behaves differently depending on whether the property has been present in the class declaration, or has been added dynamically, if the variable has been unset()

<?php

class TestClass {

    public
$declared = null;
   
}

$testObject = new TestClass;

var_dump(property_exists("TestClass", "dynamic")); // boolean false, as expected
var_dump(property_exists($testObject, "dynamic")); // boolean false, same as above

$testObject->dynamic = null;
var_dump(property_exists($testObject, "dynamic")); // boolean true

unset($testObject->dynamic);
var_dump(property_exists($testObject, "dynamic")); // boolean false, again.

var_dump(property_exists($testObject, "declared")); // boolean true, as espected

unset($testObject->declared);
var_dump(property_exists($testObject, "declared")); // boolean true, even if has been unset()
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17
Stefan W
3 years ago
If you are in a namespaced file, and you want to pass the class name as a string, you will have to include the full namespace for the class name - even from inside the same namespace:

<?
namespace MyNS;

class
A {
    public
$foo;
}

property_exists("A", "foo");          // false
property_exists("\\MyNS\\A", "foo");  // true
?>
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9
Nanhe Kumar
2 years ago
<?php

class Student {

    protected
$_name;
    protected
$_email;
   

    public function
__call($name, $arguments) {
       
$action = substr($name, 0, 3);
        switch (
$action) {
            case
'get':
               
$property = '_' . strtolower(substr($name, 3));
                if(
property_exists($this,$property)){
                    return
$this->{$property};
                }else{
                    echo
"Undefined Property";
                }
                break;
            case
'set':
               
$property = '_' . strtolower(substr($name, 3));
                if(
property_exists($this,$property)){
                   
$this->{$property} = $arguments[0];
                }else{
                    echo
"Undefined Property";
                }
               
                break;
            default :
                return
FALSE;
        }
    }

}

$s = new Student();
$s->setName('Nanhe Kumar');
$s->setEmail('nanhe.kumar@gmail.com');
echo
$s->getName(); //Nanhe Kumar
echo $s->getEmail(); // nanhe.kumar@gmail.com
$s->setAge(10); //Undefined Property
?>
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2
saurabh dot agarwal89 at gmail dot com
1 year ago
$a = array('a','b'=>'c');
print_r((object) $a);
var_dump( property_exists((object) $a,'0'));
var_dump( property_exists((object) $a,'b'));

OUTPUT:
stdClass Object
(
    [0] => a
    [b] => c
)
bool(false)
bool(true)
up
1
ewisuri [gmail]
2 years ago
As of PHP 5.3.0, calling property_exists from a parent class sees private properties in sub-classes.

<?php
class P {
    public function
test_prop($prop) { return property_exists($this, $prop); }
}

class
Child extends P {
    private
$prop1;
}

$child = new Child();
var_dump($child->test_prop('prop1')); //true, as of PHP 5.3.0
up
0
Daniel dot Peder at infoset dot com
12 days ago
declared properties cannot be unset
any set property does exist, even being set to null, regardless how it was set

<?php

class demo_property_exists {

    public
$my_public;
    protected
$my_protected;
    private
$my_private;

    function
__construct() {
       
$this->dumper('before-constructed');
       
$this->my_constructed_int = 123;
       
$this->my_constructed_null = null;
       
$this->dumper('after-constructed');
    }

    public function
dumper($name) {
       
printf("\n[%s] dump:\n", $name);

        foreach (
$this->my_checklist() as $prop) {
           
printf("[%s]:\t", $prop);
           
var_dump(property_exists($this, $prop));
        }
    }

    public function
unset_all() {
        foreach (
$this->my_checklist() as $prop) {
            unset(
$this->$prop);
        }
    }

    private function
my_checklist() {
        return array(
'my_public', 'my_protected', 'my_private', 'my_constructed_int', 'my_constructed_null', 'my_assigned_int', 'my_assigned_null',);
    }

}

$object = new demo_property_exists();
$object->dumper('before-assigned');
$object->my_assigned_int = 456;
$object->my_assigned_null = null;
$object->dumper('after-assigned');
$object->unset_all();
$object->dumper('after-unset');

/*
results:

[before-constructed] dump:
[my_public]:    bool(true)
[my_protected]: bool(true)
[my_private]:   bool(true)
[my_constructed_int]:   bool(false)
[my_constructed_null]:  bool(false)
[my_assigned_int]:      bool(false)
[my_assigned_null]:     bool(false)

[after-constructed] dump:
[my_public]:    bool(true)
[my_protected]: bool(true)
[my_private]:   bool(true)
[my_constructed_int]:   bool(true)
[my_constructed_null]:  bool(true)
[my_assigned_int]:      bool(false)
[my_assigned_null]:     bool(false)

[before-assigned] dump:
[my_public]:    bool(true)
[my_protected]: bool(true)
[my_private]:   bool(true)
[my_constructed_int]:   bool(true)
[my_constructed_null]:  bool(true)
[my_assigned_int]:      bool(false)
[my_assigned_null]:     bool(false)

[after-assigned] dump:
[my_public]:    bool(true)
[my_protected]: bool(true)
[my_private]:   bool(true)
[my_constructed_int]:   bool(true)
[my_constructed_null]:  bool(true)
[my_assigned_int]:      bool(true)
[my_assigned_null]:     bool(true)

[after-unset] dump:
[my_public]:    bool(true)
[my_protected]: bool(true)
[my_private]:   bool(true)
[my_constructed_int]:   bool(false)
[my_constructed_null]:  bool(false)
[my_assigned_int]:      bool(false)
[my_assigned_null]:     bool(false)

*/
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