property_exists

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

    property_exists — Verifica se o objeto ou a classe tem uma propriedade

    Descrição

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

    Essa função verifica se a propriedade informada em property existe na classe especificada.

    Nota:

    Ao contrário de isset(), property_exists() retorna true mesmo se a propriedade tiver o valor null.

    Parâmetros

    object_or_class

    O nome da classe ou um objeto da classe a ser testada

    property

    O nome da propriedade

    Valor Retornado

    Retorna true se a propriedade existe, false se ela não existir.

    Exemplos

    Exemplo #1 Exemplo de property_exists()

    <?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();

    ?>

    Notas

    Nota:

    Usar esta função fará com que qualquer autoloader registrado seja usado se a classe ainda não for conhecida.

    Nota:

    A função property_exists() não consegue detectar propriedades que são magicamente acessíveis usando o método mágico __get.

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    Notas Enviadas por Usuários (em inglês) 6 notes

    up
    68
    g dot gentile at parentesigraffe dot com
    10 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
    26
    Stefan W
    11 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
    14
    Nanhe Kumar
    11 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
    6
    ewisuri [gmail]
    11 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
    4
    saurabh dot agarwal89 at gmail dot com
    9 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
    -2
    biziclop
    1 year 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.
    */
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