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
    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
    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
    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
    6
    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
    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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