PHP Velho Oeste 2024

property_exists

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

property_exists Checks if the object or class has a property

Description

property_exists(object|string $object_or_class, string $property): bool

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

object_or_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.

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
var_dump(property_exists('myClass', 'bar')); //false
var_dump(property_exists('myClass', 'test')); //true
myClass::test();

?>

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.

See Also

add a note add a note

User Contributed Notes 6 notes

up
71
g dot gentile at parentesigraffe dot com
9 years 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()
up
25
Stefan W
10 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
?>
up
15
Nanhe Kumar
10 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
?>
up
5
ewisuri [gmail]
10 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
3
saurabh dot agarwal89 at gmail dot com
8 years 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
0
biziclop
6 months ago
I needed a method for finding out if accessing a property outside a class is possible without errors/warnings, considering that the class might use the magic methods __isset/__get to simulate nonexistent properties.

<?php
// returns true if property is safely accessible publicly by using $obj->$prop
// Tested with PHP 5.1 - 8.2, see https://3v4l.org/QBTd1
function public_property_exists( $obj, $prop ){
 
// allow magic $obj->__isset( $prop ) to execute if exists
 
if( isset( $obj->$prop ))  return true;
 
 
// no public/protected/private property exists with this name
 
if( ! property_exists( $obj, $prop ))  return false;

 
// the property exists, but is it public?
 
$rp = new ReflectionProperty( $obj, $prop );
  return
$rp->isPublic();
}

//// Test/demo
class C {
  public   
$public    = "I’m public!";
  protected
$protected = "I’m public!";
  private  
$private   = "I’m public!";
  function
__isset( $k ){
    return
substr( $k, 0, 5 ) === 'magic';
  }
  function
__get( $k ){
    if(
$k === 'magic_isset_but_null')  return null;
    return
"I’m {$k}!";
  }
}

$o = new C();
foreach( array(
 
'public', 'protected', 'private',
 
'magic', 'magic_isset_but_null',
 
'missing'
) as $prop ){
  if(
public_property_exists( $o, $prop ))
        echo
"\$o->{$prop} is a public property, its value is: ",
            
var_export( $o->$prop, true ), "\n";
  else  echo
"\$o->{$prop} is not a public property.\n";
}
/*
$o->public    is a public property, its value is: 'I’m public!'
$o->protected is not a public property.
$o->private   is not a public property.
$o->magic     is a public property, its value is: 'I’m magic!'
$o->magic_isset_but_null is a public property, its value is: NULL
$o->missing   is not a public property.
*/
To Top