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Last updated: Sat, 27 Jan 2007

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# method_exists

(PHP 4, PHP 5)

method_exists -- Проверяет существует ли метод в данном классе

## Описание

bool method_exists ( object object, string method_name )

Функция возвращает `TRUE` если метод `method_name` был объявлен для `object`. В противном случае функция возвращает `FALSE`.

Пример 1. Пример использования method_exists()

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

выведет:

    bool(true)

add a note User Contributed Notes
method_exists
04-Dec-2006 02:14
`Not (yet) mentioned in the docs: since PHP 5 the first argument may also be a string with the class name:
class foo {
function bar () {}
}
var_dump(method_exists('foo','bar'));
Will output bool(true) - however note that this won't work in PHP 4. When running PHP 4 this will output bool(false).
Tested with PHP 5.1 / PHP 4.3`
jp at function dot fi
30-Apr-2006 02:29
`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)
?>`
seufert at gmail dot com
26-Apr-2006 06:27
`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.`
spam at majiclab dot com
31-Jan-2006 08:33
`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 $instance of a class or the 'ClassName' to get only public functions.`
daniel at softel dot jp
09-Jan-2006 07:34
`Note that in PHP5, method_exists() will sucessfully find *private* methods. This has some OO/data-hiding ramifications.`
jpgiot at nospam ifrance.com
06-May-2004 07:42
`a little difference :
to find a method of an object (instance of a class)
<?php
if (method_exists($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';
?>`
Thomas@ThBeckmann
31-Jan-2003 01:47
`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>))`
benjamin_ansbach at web dot de
27-Dec-2002 12:49
`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`
j dot metzger at steptown dot com
16-Jan-2002 03:42
`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.`
add a note
property_exists is_subclass_of

Last updated: Sat, 27 Jan 2007
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