PHP 5.4.33 Released

method_exists

(PHP 4, PHP 5)

method_existsComprueba si existe un método de una clase

Descripción

bool method_exists ( mixed $object , string $method_name )

Comprueba si existe el método de la clase en el objeto dado por object.

Parámetros

object

Una instancia o un nombre de clase

method_name

El nombre del método

Valores devueltos

Devuelve TRUE si el método dado por method_name ha sido definido para el objeto dado por object, FALSE si no.

Notas

Nota:

Esta función cargará cualquier autocargador registrado si la clase todavía no existe.

Ejemplos

Ejemplo #1 Ejemplo de method_exists()

<?php
$directorio 
= new Directory('.');
var_dump(method_exists($directorio,'read'));
?>

El resultado del ejemplo sería:

bool(true)

Ejemplo #2 Ejemplo de method_exists() estático

<?php
var_dump
(method_exists('Directory','read'));
?>

El resultado del ejemplo sería:

bool(true)

Ver también

  • function_exists() - Devuelve TRUE si la función dada ha sido definida
  • is_callable() - Verificar que los contenidos de una variable puedan ser llamados como una función
  • class_exists() - Verifica si la clase ha sido definida

add a note add a note

User Contributed Notes 16 notes

up
15
phoenix at todofixthis dot com
3 years ago
As noted [elsewhere] method_exists() does not care about the existence of __call(), whereas is_callable() does:

<?php
class Test {
  public function
explicit(  ) {
     
// ...
 
}
  
  public function
__call( $meth, $args ) {
     
// ...
 
}
}

$Tester = new Test();

var_export(method_exists($Tester, 'anything')); // false
var_export(is_callable(array($Tester, 'anything'))); // true
?>
up
4
jp at function dot fi
8 years ago
As mentioned before, is_callable and method_exists report all methods callable even if they are private/protected and thus actually not callable. So instead of those functions you may use following work-around which reports methods as supposed to.

<?php
class Foo1 {
  public function
bar() {
    echo
"I'm private Foo1::bar()";
  }
}

class
Foo2 {
  private function
bar() {
    echo
"I'm public Foo2::bar()";
  }
}

$f1=new Foo1;
$f2=new Foo2;

if(
is_callable(array($f1,"bar"))) {
    echo
"Foo1::bar() is callable";
} else {
    echo
"Foo1::bar() isn't callable";
}
if(
is_callable(array($f2,"bar"))) {
    echo
"Foo2::bar() is callable";
} else {
    echo
"Foo2::bar() isn't callable";
}
if(
in_array("bar",get_class_methods($f1))) {
    echo
"Foo1::bar() is callable";
} else {
    echo
"Foo1::bar() isn't callable";
}
if(
in_array("bar",get_class_methods($f2))) {
    echo
"Foo2::bar() is callable";
} else {
    echo
"Foo2::bar() isn't callable";
}

?>

output
Foo1::bar() is callable (correct)
Foo2::bar() is callable (incorrect)
Foo1::bar() is callable (correct)
Foo2::bar() isn't callable (correct)

?>
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4
Niels
3 years ago
Just to mention it: both method_exists() and is_callable() return true for inherited methods:

<?php
class ParentClass {

   function
doParent() { }
}

class
ChildClass extends ParentClass { }

$p = new ParentClass();
$c = new ChildClass();

// all return true
var_dump(method_exists($p, 'doParent'));
var_dump(method_exists($c, 'doParent'));

var_dump(is_callable(array($p, 'doParent')));
var_dump(is_callable(array($c, 'doParent')));
?>
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2
konzertheld at thedomainistheusersname dot de
1 year ago
Note that prepending the namespace (if any) is required even if the calling class is in the same namespace:

<?php
namespace test;
class
foo {
public function
lookup() {
 
// will return false
 
return method_exists('bar', 'nonsense_method');
}
}

class
bar {
public function
nonsense_method() {
 
// will return true
 
return method_exists('test\foo', 'lookup');
}
}
?>
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2
mail at bartrail dot de
3 years ago
Using method_exists inside an object's __call() method can be very usefull if you want to avoid to get a fatal error because of a limit in function nesting or if you are calling methods that dont exist but need to continue in your application:

<?php
class Something
{

   
/**
     * Call a method dynamically
     *
     * @param string $method
     * @param array $args
     * @return mixed
     */
   
public function __call($method, $args)
    {
        if(
method_exists($this, $method)) {
          return
call_user_func_array(array($this, $method), $args);
        }else{
          throw new
Exception(sprintf('The required method "%s" does not exist for %s', $method, get_class($this)));
        }
    }

}
?>
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2
admin ( at ) djokodonev dot com
4 years ago
Hi,

Here is a useful function that  you can use to check classes methods access e.g whether it is public, private or static or both..

here it goes:

<?php
// Example class
class myClass {

    private
$private1;
   
    static
$static1;
   
    public
$public1;
       
   
    public function
publ() {
   
    }
   
    private function
priv() {
   
    }
   
    private static function
privstatic() {

    }
   
    public static function
publstatic() {
   
    }
   
    static function
mytest() {
   
    }
}

// The function uses the reflection class that is built into PHP!!!
// The purpose is to determine the type of a certain method that exi
function is_class_method($type="public", $method, $class) {
  
// $type = mb_strtolower($type);
   
$refl = new ReflectionMethod($class, $method);
    switch(
$type) {
        case
"static":
        return
$refl->isStatic();
        break;
        case
"public":
        return
$refl->isPublic();
        break;
        case
"private":
        return
$refl->isPrivate();
        break;
    }
}
var_dump(is_class_method("static", "privstatic", "myClass")); // true - the method is  private and also static..
var_dump(is_class_method("private", "privstatic", "myClass")); // true - the method is  private and also static..
var_dump(is_class_method("private", "publstatic", "myClass")); // False the methos is public and also static not private
// you get the idea.. I hope this helps someone..
?>
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2
daniel at softel dot jp
8 years ago
Note that in PHP5, method_exists() will sucessfully find *private* methods. This has some OO/data-hiding ramifications.
up
1
florin from syneto net
4 years ago
This function is case-insensitive (as is PHP) and here is the proof:
<?php
class A {
    public function
FUNC() { echo '*****'; }
}

$a = new A();
$a->func(); // *****
var_dump(method_exists($a, 'func')); // bool(true)
?>
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2
uramihsayibok, gmail, com
4 years ago
It wasn't spelled out but could be inferred: method_exists() also works on interfaces.

<?php

var_dump
(method_exists("Iterator", "current"));
// bool(true)

?>
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1
benjamin_ansbach at web dot de
11 years ago
if you want to check for a method "inside" of a class use:

method_exists($this, 'function_name')

i was a bit confused 'cause i thought i'm only able to check for a method when i got an object like $object_name = new class_name() with:

method_exists($object_name, 'method_name')

small example for those who didn't understood what i mean ( maybe caused by bad english :) ):

<?php

class a {

    function
a() {
       
        if(
method_exists($this, 'test'))
            echo
'a::test() exists!';
        else
            echo
'a::test() doesn\'t exists';

    }

   
    function
test() {
       
        return
true;
   
    }

}

$b = new a();

?>

the output will be: a::test() exists!

maybe this will help someone
up
0
seufert at gmail dot com
8 years ago
Just a note that the behaviour of this function changed between version 5.0.x and 5.1.x when using static member functions

Using this code:
<?php
class a {
    static function
test() {return "A";}
}
if(
method_exists('a','test'))
    print
call_user_func(array('a','test'));
else
    print
"Nothing";
?>
PHP 5.1.x returns "A"
PHP 5.0.x returns "Nothing"

Im not sure of a workaround for PHP 5.0.x yet.
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0
spam at majiclab dot com
8 years ago
Both method_exists() and is_callable() return private and protected functions, which, as mentioned below, causes problems for PHP5/OO programming.  You can use get_class_methods() with either an $instance of a class or the 'ClassName' to get only public functions.
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0
jpgiot at nospam ifrance.com
10 years ago
a little difference :

to find a method of an object (instance of a class)

<?php
if (method_exists($myinstance,'themethod'))
    echo
'ok';
?>

to find a method of a class (using the class name, not the instance of the class!)

<?php
if (is_callable(array('theclassname','themethod')))
    echo
'ok';
?>
up
0
Thomas@ThBeckmann
11 years ago
Though, as Bejamin noted, it's not possible to use the class name in method_exists within the class definition, get_class_methods delivers the method names for a given class name even inside the class. Thus another workaround for the mentioned problem is to use in_array(<method_name>, get_class_methods(<class_name>))
up
0
j dot metzger at steptown dot com
12 years ago
call_user_method uses the same mechanism as a normal method call. So you can get the returned values as well in this way.

$pagetext=call_user_method($method,$object_call);

All information is then in $pagetext.
up
-1
Anonymous
4 years ago
If you want to check in a class itself if a method is known you may do so with magic variable __CLASS__

<?php

class A{
 
__construct($method){
      return
method_exists(__CLASS__,$method);
  }

  private function
foo(){
 
  }
}

$test = new A('foo');
//should return true

?>

You might also use the method describe below with <?php in_array() ?> trick but I consider this one here easier and more readable and well, the way it is intended toi be done ;)
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