method_exists
This function is case-sensitive, so :
<?php
class Test {
public $property;
public foo() { echo($property); }
}
property_exists('Test', 'property'); // will return true
property_exists('Test', 'Property'); // will return false
?>
(under PHP5.1.2)
property_exists
(PHP 5 >= 5.1.0)
property_exists — Checa se o objeto ou a classe tem uma propriedade
Descrição
Essa função checa se property existe na
classe especificada (e se ela é acessível do escopo atual).
Nota:
Ao contrário de isset(), property_exists() retorna
TRUEmesmo se a propriedade tiver valorNULL(nulo).
Parâmetros
-
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 ou
NULL em caso de erro.
Exemplos
Exemplo #1 Exemplo de uso de property_exists()
<?php
class myClass {
public $mine;
private $xpto;
static function test() {
var_dump(property_exists('myClass', 'xpto')); // true, it can be accessed from here
}
}
var_dump(property_exists('myClass', 'mine')); //true
var_dump(property_exists(new myClass, 'mine')); //true
var_dump(property_exists('myClass', 'xpto')); //false, isn't public
myClass::test();
?>
add a note
User Contributed Notes
property_exists - [5 notes]
Alan71 ¶
6 years ago
webmaster at thedigitalorchard dot ca ¶
3 years ago
According to my tests, isset() is 4 times faster than property_exists(), so use a combination of these functions in your programming for best performance.
For example:
<?php
$fld = 'somevar';
if (isset($this->$fld) || property_exists($this, $fld)) {
}
?>
If your programming routinely checks a larger number of property names that are expected to exist, whereas a smaller number may not, then using isset(), as above, will result in faster execution of the programming.
rayro at gmx dot de ¶
5 years ago
To check the existance of a property from outside the scope (even if it's not accessible) try/consider the following:
<?php
function property_exists_safe($class, $prop)
{
$r = property_exists($class, $prop);
if (!$r) {
$x = new ReflectionClass($class);
$r = $x->hasProperty($prop);
}
return $r;
}
class myClass {
public $mine;
private $xpto;
static function test1() {
// true, it can be accessed from here
var_dump(property_exists('myClass', 'xpto'));
}
static function test2() {
// true, it can be accessed from everywhere!
var_dump(property_exists_safe('myClass', 'xpto'));
}
}
var_dump(property_exists('myClass', 'mine')); //true
var_dump(property_exists(new myClass, 'mine')); //true
var_dump(property_exists('myClass', 'xpto')); //false, isn't public
myClass::test1();
echo("\n");
var_dump(property_exists_safe('myClass', 'mine')); //true
var_dump(property_exists_safe(new myClass, 'mine')); //true
var_dump(property_exists_safe('myClass', 'xpto')); //true
myClass::test2(); //true
?>
bool(true)
bool(true)
bool(false)
bool(true)
bool(true)
bool(true)
bool(true)
bool(true)
jcaplan at bogus dot amazon dot com ¶
6 years ago
The documentation leaves out the important case of new properties you add to objects at run time. In fact, property_exists will return true if you ask it about such properties.
<?php
class Y {}
$y = new Y;
echo isset( $y->prop ) ? "yes\\n" : "no\\n"; // no;
echo property_exists( 'Y', 'prop' ) ? "yes\\n" : "no\\n"; // no
echo property_exists( $y, 'prop' ) ? "yes\\n" : "no\\n"; // no
$y->prop = null;
echo isset( $y->prop ) ? "yes\\n" : "no\\n"; // no;
echo property_exists( 'Y', 'prop' ) ? "yes\\n" : "no\\n"; // no
echo property_exists( $y, 'prop' ) ? "yes\\n" : "no\\n"; // yes
?>
timshel ¶
7 years ago
I haven't tested this with the exact function semantics of 5.1, but this code should implement this function in php < 5.1:
<?php
if (!function_exists('property_exists')) {
function property_exists($class, $property) {
if (is_object($class))
$class = get_class($class);
return array_key_exists($property, get_class_vars($class));
}
}
?>