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isset

(PHP 4, PHP 5, PHP 7)

issetInforma se a variável foi iniciada

Descrição

bool isset ( mixed $var [, mixed $var [, $... ]] )

Verifica se a variável é definida.

Se a variável for destruída com unset(), ela não existirá mais. isset() retornará FALSE se for usada em uma variável com o valor NULL. Lembrando que no PHP um byte NULL ("\0") é diferente da constante NULL.

Se múltiplos parâmetros são fornecidos, então isset() retornará TRUE somente se todos os parâmetros são definidos. A avaliação vai da esquerda para direita e pára logo que encontra uma variável não definida.

Parâmetros

var

A variável a ser verificada.

var

Outra variável...

...

Valor Retornado

Retorna TRUE se var existe; FALSE caso contrário.

Exemplos

Exemplo #1 Exemplos da isset()

<?php

$var 
'';

// Será interpretado como TRUE imprimindo o texto.
if (isset($var)) {
    echo 
"Essa variável existe.";
}

// No próximo exemplo será usado var_dump para mostrar
// o valor de retorno de isset().

$a "teste";
$b "outrotest";

var_dump( isset($a) );      // TRUE
var_dump( isset ($a$b) ); // TRUE

unset ($a);

var_dump( isset ($a) );     // FALSE
var_dump( isset ($a$b) ); // FALSE

$foo NULL;
var_dump( isset ($foo) );   // FALSE

?>

Isto também serve para chaves associativas de matrizes:

<?php

$a 
= array ('test' => 1'hello' => NULL);

var_dump( isset ($a['test']) );            // TRUE
var_dump( isset ($a['foo']) );             // FALSE
var_dump( isset ($a['hello']) );           // FALSE

// A chave 'hello' é igual a NULL sendo considerada como inexistente
// Se quiser verificar o valor NULL da chave tente:
var_dumparray_key_exists('hello'$a) ); // TRUE

?>

Notas

Aviso

isset() somente funciona com variáveis, passando qualquer outra coisa resultará em um erro do analisador. Para verificar se constants estão definidas, use a função defined().

Nota: Este é um construtor de linguagem e não uma função, por isso não é possível chamá-lo através de funções variáveis

Veja Também

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User Contributed Notes 55 notes

up
19
p_ignorethis_lbowers at gmail dot com
1 year ago
I, too, was dismayed to find that isset($foo) returns false if ($foo == null). Here's an (awkward) way around it.

unset($foo);
if (compact('foo') != array()) {
  do_your_thing();
}

Of course, that is very non-intuitive, long, hard-to-understand, and kludgy. Better to design your code so you don't depend on the difference between an unset variable and a variable with the value null. But "better" only because PHP has made this weird development choice.

In my thinking this was a mistake in the development of PHP. The name ("isset") should describe the function and not have the desciption be "is set AND is not null". If it was done properly a programmer could very easily do (isset($var) || is_null($var)) if they wanted to check for this!

A variable set to null is a different state than a variable not set - there should be some easy way to differentiate. Just my (pointless) $0.02.
up
50
beuc at beuc dot net
10 years ago
"empty() is the opposite of (boolean) var, except that no warning is generated when the variable is not set."

So essentially
<?php
if (isset($var) && $var)
?>
is the same as
<?php
if (!empty($var))
?>
doesn't it? :)

!empty() mimics the chk() function posted before.
up
40
yaogzhan at gmail dot com
12 years ago
in PHP5, if you have

<?PHP
class Foo
{
    protected
$data = array('bar' => null);

    function
__get($p)
    {
        if( isset(
$this->data[$p]) ) return $this->data[$p];
    }
}
?>

and
<?PHP
$foo
= new Foo;
echo isset(
$foo->bar);
?>
will always echo 'false'. because the isset() accepts VARIABLES as it parameters, but in this case, $foo->bar is NOT a VARIABLE. it is a VALUE returned from the __get() method of the class Foo. thus the isset($foo->bar) expreesion will always equal 'false'.
up
34
Daniel Klein
5 years ago
How to test for a variable actually existing, including being set to null. This will prevent errors when passing to functions.

<?php
// false
var_export(
 
array_key_exists('myvar', get_defined_vars())
);

$myvar;
// false
var_export(
 
array_key_exists('myvar', get_defined_vars())
);

$myvar = null;
// true
var_export(
 
array_key_exists('myvar', get_defined_vars())
);

unset(
$myvar);
// false
var_export(
 
array_key_exists('myvar', get_defined_vars())
);

if (
array_key_exists('myvar', get_defined_vars())) {
 
myfunction($myvar);
}
?>

Note: you can't turn this into a function (e.g. is_defined($myvar)) because get_defined_vars() only gets the variables in the current scope and entering a function changes the scope.
up
21
mandos78 AT mail from google
9 years ago
Careful with this function "ifsetfor" by soapergem, passing by reference means that if, like the example $_GET['id'], the argument is an array index, it will be created in the original array (with a null value), thus causing posible trouble with the following code. At least in PHP 5.

For example:

<?php
$a
= array();
print_r($a);
ifsetor($a["unsetindex"], 'default');
print_r($a);
?>

will print

Array
(
)
Array
(
    [unsetindex] =>
)

Any foreach or similar will be different before and after the call.
up
22
Anonymous
11 years ago
I tried the example posted previously by Slawek:

$foo = 'a little string';
echo isset($foo)?'yes ':'no ', isset($foo['aaaa'])?'yes ':'no ';

He got yes yes, but he didn't say what version of PHP he was using.

I tried this on PHP 5.0.5 and got:  yes no

But on PHP 4.3.5 I got:  yes yes

Apparently, PHP4 converts the the string 'aaaa' to zero and then returns the string character at that position within the string $foo, when $foo is not an array. That means you can't assume you are dealing with an array, even if you used an expression such as isset($foo['aaaa']['bbb']['cc']['d']), because it will return true also if any part is a string.

PHP5 does not do this. If $foo is a string, the index must actually be numeric (e.g. $foo[0]) for it to return the indexed character.
up
18
muratyaman at gmail dot com
9 years ago
To organize some of the frequently used functions..

<?php

/**
* Returns field of variable (arr[key] or obj->prop), otherwise the third parameter
* @param array/object $arr_or_obj
* @param string $key_or_prop
* @param mixed $else
*/
function nz($arr_or_obj, $key_or_prop, $else){
 
$result = $else;
  if(isset(
$arr_or_obj)){
    if(
is_array($arr_or_obj){
      if(isset(
$arr_or_obj[$key_or_prop]))
       
$result = $arr_or_obj[$key_or_prop];
    }elseif(
is_object($arr_or_object))
      if(isset(
$arr_or_obj->$key_or_prop))
       
$result = $arr_or_obj->$key_or_prop;
    }
  }
  return
$result;
}

/**
* Returns integer value using nz()
*/
function nz_int($arr_or_obj, $key_or_prop, $else){
  return
intval(nz($arr_or_obj, $key_or_prop, $else));
}

$my_id = nz_int($_REQUEST, 'id', 0);
if(
$my_id > 0){
 
//why?
}
?>
up
16
francois vespa
6 years ago
Now this is how to achieve the same effect (ie, having isset() returning true even if variable has been set to null) for objects and arrays

<?php

// array

$array=array('foo'=>null);

return isset(
$array['foo']) || array_key_exists('foo',$array)
  ?
true : false ; // return true

return isset($array['inexistent']) || array_key_exists('inexistent',$array)
  ?
true : false ; // return false

// static class

class bar

{
  static
$foo=null;
}

return isset(
bar::$foo) || array_key_exists('foo',get_class_vars('bar'))
  ?
true : false ; // return true

return isset(bar::$inexistent) || array_key_exists('inexistent',get_class_vars('bar'))
  ?
true : false ; // return false

// object

class bar
{
    public
$foo=null;
}

$bar=new bar();

return isset(
$bar->foo) || array_key_exists('foo',get_object_vars($bar))
  ?
true : false ; // return true

return isset($bar->inexistent) || array_key_exists('inexistent',get_object_vars($bar))
  ?
true : false ; // return true

// stdClass

$bar=new stdClass;
$bar->foo=null;

return isset(
$bar->foo) || array_key_exists('foo',get_object_vars($bar))
  ?
true : false ; // return true

return isset($bar->inexistent) || array_key_exists('inexistent',get_object_vars($bar))
  ?
true : false ; // return true

?>
up
6
andreasonny83 at gmail dot com
2 years ago
Here is an example with multiple parameters supplied

<?php
$var
= array();
$var['val1'] = 'test';
$var['val2'] = 'on';

if ( isset(
$var['val1'], $var['val2'] ) && $var['val2'] === 'on' ) {
    unset(
$var['val1'] );
}
print_r( $var );
?>

This will output:
Array
(
    [val2] => on
)

The following code does the same calling "isset" 2 times:

<?php
$var
= array();
$var['val1'] = 'test';
$var['val2'] = 'on';

if ( isset(
$var['val1'] ) && isset( $var['val2'] ) && $var['val2'] === 'on' ) {
    unset(
$var['val1'] );
}
print_r( $var );
?>
up
15
a dot schaffhirt at sedna-soft dot de
9 years ago
You can safely use isset to check properties and subproperties of objects directly. So instead of writing

    isset($abc) && isset($abc->def) && isset($abc->def->ghi)

or in a shorter form

    isset($abc, $abc->def, $abc->def->ghi)

you can just write

    isset ($abc->def->ghi)

without raising any errors, warnings or notices.

Examples
<?php
    $abc
= (object) array("def" => 123);
   
var_dump(isset($abc));                // bool(true)
   
var_dump(isset($abc->def));           // bool(true)
   
var_dump(isset($abc->def->ghi));      // bool(false)
   
var_dump(isset($abc->def->ghi->jkl)); // bool(false)
   
var_dump(isset($def));                // bool(false)
   
var_dump(isset($def->ghi));           // bool(false)
   
var_dump(isset($def->ghi->jkl));      // bool(false)

   
var_dump($abc);                       // object(stdClass)#1 (1) { ["def"] => int(123) }
   
var_dump($abc->def);                  // int(123)
   
var_dump($abc->def->ghi);             // null / E_NOTICE: Trying to get property of non-object
   
var_dump($abc->def->ghi->jkl);        // null / E_NOTICE: Trying to get property of non-object
   
var_dump($def);                       // null / E_NOTICE: Trying to get property of non-object
   
var_dump($def->ghi);                  // null / E_NOTICE: Trying to get property of non-object
   
var_dump($def->ghi->jkl);             // null / E_NOTICE: Trying to get property of non-object
?>
up
16
Andrew Penry
12 years ago
The following is an example of how to test if a variable is set, whether or not it is NULL. It makes use of the fact that an unset variable will throw an E_NOTICE error, but one initialized as NULL will not.

<?php

function var_exists($var){
    if (empty(
$GLOBALS['var_exists_err'])) {
        return
true;
    } else {
        unset(
$GLOBALS['var_exists_err']);
        return
false;
    }
}

function
var_existsHandler($errno, $errstr, $errfile, $errline) {
  
$GLOBALS['var_exists_err'] = true;
}

$l = NULL;
set_error_handler("var_existsHandler", E_NOTICE);
echo (
var_exists($l)) ? "True " : "False ";
echo (
var_exists($k)) ? "True " : "False ";
restore_error_handler();

?>

Outputs:
True False

The problem is, the set_error_handler and restore_error_handler calls can not be inside the function, which means you need 2 extra lines of code every time you are testing. And if you have any E_NOTICE errors caused by other code between the set_error_handler and restore_error_handler they will not be dealt with properly. One solution:

<?php

function var_exists($var){
   if (empty(
$GLOBALS['var_exists_err'])) {
       return
true;
   } else {
       unset(
$GLOBALS['var_exists_err']);
       return
false;
   }
}

function
var_existsHandler($errno, $errstr, $errfile, $errline) {
   
$filearr = file($errfile);
    if (
strpos($filearr[$errline-1], 'var_exists') !== false) {
       
$GLOBALS['var_exists_err'] = true;
        return
true;
    } else {
        return
false;
    }
}

$l = NULL;
set_error_handler("var_existsHandler", E_NOTICE);
echo (
var_exists($l)) ? "True " : "False ";
echo (
var_exists($k)) ? "True " : "False ";
is_null($j);
restore_error_handler();

?>

Outputs:
True False
Notice: Undefined variable: j in filename.php on line 26

This will make the handler only handle var_exists, but it adds a lot of overhead. Everytime an E_NOTICE error happens, the file it originated from will be loaded into an array.
up
15
Slawek Petrykowski
11 years ago
<?php
$foo
= 'a little string';
echo isset(
$foo)?'yes ':'no ', isset($foo['aaaa'])?'yes ':'no ';
>

results with unexpected values:
yes yes

Well
, it is necessary to check type of $foo first !
up
13
anonymousleaf at gmail dot com
9 years ago
isset expects the variable sign first, so you can't add parentheses or anything.

<?php
    $foo
= 1;
    if(isset((
$foo))) { // Syntax error at isset((
       
$foo = 2;
    }
?>
up
8
uramihsayibok, gmail, com
4 years ago
Note that isset() is not recursive as of the 5.4.8 I have available here to test with: if you use it on a multidimensional array or an object it will not check isset() on each dimension as it goes.

Imagine you have a class with a normal __isset and a __get that fatals for non-existant properties. isset($object->nosuch) will behave normally but isset($object->nosuch->foo) will crash. Rather harsh IMO but still possible.

<?php

class FatalOnGet {

   
// pretend that the methods have implementations that actually try to do work
    // in this example I only care about the worst case conditions

   
public function __get($name) {
        echo
"(getting {$name}) ";

       
// if property does not exist {
           
echo "Property does not exist!";
            exit;
       
// }
   
}

    public function
__isset($name) {
        echo
"(isset {$name}?) ";
       
// return whether the property exists
       
return false;
    }

}

$obj = new FatalOnGet();

// works
echo "Testing if ->nosuch exists: ";
if (isset(
$obj->nosuch)) echo "Yes"; else echo "No";

// fatals
echo "\nTesting if ->nosuch->foo exists: ";
if (isset(
$obj->nosuch->foo)) echo "Yes"; else echo "No";

// not executed
echo "\nTesting if ->irrelevant exists: ";
if (isset(
$obj->irrelevant)) echo "Yes"; else echo "No";

?>

    Testing if ->nosuch exists: No
    Testing if ->nosuch->foo exists: Property does not exist!

Uncomment the echos in the methods and you'll see exactly what happened:

    Testing if ->nosuch exists: (isset nosuch?) No
    Testing if ->nosuch->foo exists: (getting nosuch) Property does not exist!

On a similar note, if __get always returns but instead issues warnings or notices then those will surface.
up
12
soywiz at php dot net
11 years ago
Sometimes you have to check if an array has some keys. To achieve it you can use "isset" like this: isset($array['key1'], $array['key2'], $array['key3'], $array['key4'])
You have to write $array all times and it is reiterative if you use same array each time.

With this simple function you can check if an array has some keys:

<?php
function isset_array() {
    if (
func_num_args() < 2) return true;
   
$args = func_get_args();
   
$array = array_shift($args);
    if (!
is_array($array)) return false;
    foreach (
$args as $n) if (!isset($array[$n])) return false;
    return
true;
ss="default">2

U1eowns"defng class="user">Andrew Penry<?php; is set, wh<?php
103061a href="/manual/vote-note.php?id=112046&03061a e=function.isset&vote=down" title="V03061" class="usernotes-voteu">up
up
8
<03061a urami03061a p dot net
function isset_array[Th (!isset_span>array_shift(;
ss="default">2
array_shift[;

'able h u
Th)ass="2ran>;

'able h u
Th)ass="; rets="default">false   'able h u
Th)ass="; rets pan class="default">isset_array
;
ss="default">2array_shift[;

'able h isse)ass="2ran>;

'able h isse)ass="; rets="default">false   'able h isse)isset_ass="user">function isset_array[Th (!isset_span>array_shift(;
ss="default">2
array_shift) {
  &nb$k)) ? <>'u
Thass="default">$foo) {
  &nb&nbsbr />Th_s w
$arissess="keyword">;

'au
Thet always returrean>;

'au
Then class="default">false   'au
Thet always retur< pan class="default">isset_array
;
ss="default">2array_shift) {
  &nb$k)) ? <>'isseass="default">$foo) {
  &nb&nbsbr />Th_s w
$arissess="keyword">;

'a br /n class="default">false;

'a br /t always returrea           'a br /n class pan class="default">isset_ass="user">
up
13
<7521a uram<7521a p dot net
7521a =hat isset() is not recursive as of the 5.4.8 I have availss="declass 'val1'] );
}
true
;
        return
isset_ass="userpan class="default">$abc->'val1'] );
}
true
return ->'val1'] );
}

This will output:
Array
(
    ault">var_ass="default"ote" id="64442">
up
12
<9950 uram<9950 p dot net
9950 h=llowing is an example of how to test if a variable :&le br />function isset_array() {
 _default">$name
) if (!isset(?) ") {
  &ult">&fault">array_shift
(array_shiftretan c ass="keyword">($array) {
  &ult">&/fault">array_shift
($array)) return &fault">array_shiftretan class="keyword">= &/fault">array_shift;
   ass="string">'var_exists_err'<; "keyword">ret} "keyword">retclass="keyword">;
ss="default">$k) if (!isset(?) ") {
  &ult">&/fault">array_shift
isset_ass="user"> a mixspan clatofiuse'su can use f>&/ clabrom wdimension &bscopm,n
9292up
up
12
9292uram9292
<&nbc-&uldv> br />good docup; &; // tfieldv) wi angus="ss="v cuc.s"note" id="64442">
up
13
<003a Slawe<003a p dot net
003a h=hat isset() is not recursive as of the 5.4.8 I have: ine you habsp; uses&nbsn>ebr ah<clasan>

902a href="/manual/vote-note.php?id=81375&a 902a h=function.isset&vote=down" title="Vo902a" class="usernotes-voteu">up
up
12
<902a Slawe<902a p dot net
902a h=hat isset() is not recursive as of the 5.4.8 I Iy resp="vyou u10-Feb- eywor "$vhe factuakean cla i)aphpclass isset_array[def   ) wce $ce cabeean clpan class="default">isset_ass="userpan class="default">$abc->array_shiftup[def   ?phpE errome kerexample cls $ap.isset_ass="userpan class="default">$abc->def   ss="default"an class="default">isset_ass="userpan class="default">$abc->array_shift;
   5"default">def   int(5t"an class="default">isset_ass="userpan class="default">$abc->def   int(5t"an claisset_array[defisset_ass="userpan class="default">$abc->array_shiftup[def   ?phppan class="default">isset_ass="userpan class="default">$abc->def   ss="default"an class="default">isset_array[defisset_ass="userpan class="default">$abc->array_shift;
   5"default">def   int(5t"an class="default">isset_ass="userpan class="default">$abc->def   ?phppan class="default">isset_ass="userbr />(
   Ir />
&nyou u) Propertys use of the frexample clunset v:n>class $abc
->$k)) ? <>'cass="default">$foo->Th_s w$arisproperty exists
   efaul pan class="default">isset_ass="userpan class="default">$abc
->def   fauarf and restorss="default">isset_ass="userpan class="default">$abc->def   &amipultrob&cra bitlas restorss="default">isset_ass="userpan class="default">$abc->defisset_ass="userpan class="default">$abc->$errno, def->
This will output:
Array$abc
->array_shift->
defisset_ass="userpan class="default">$abc->$k)) ? <>
'cass="default">$foo
->Th_s w$arisproperty exists
   ".. ?phpisset_ass="userpan class="default">$abc
->array_shift;
   class="default">set_error_handlercp       
   me keycls $c restorss="default">isset_ass="userpan class="default">$abc->$k)) ? <>'cass="default">$foo->Th_s w$arisproperty exists
    &nb!pan class="default">isset_ass="userpan class="default">$abc
->def   efaul; ine you ?phpisset_array[def   fexample an cltit restorss="default">isset_ass="userpan class="default">$abc->$k)) ? <>'cass="default">$foo->Th_s w$arisproperty exists
   efaul
This will output:
Array$abc
->array_shiftup[
defisset_ass="userpan class="default">$abc->$k)) ? <>'cass="default">$foo->Th_s w$arisproperty exists
    &nb!pan class="default">isset_array
[def   an cltit againorestorss="default">isset_ass="userpan class="default">$abcup[def   ">upisset_ass="userpan class="default">$abc->$k)) ? <>'cass="default">$foo->Th_s w$arisproperty exists
    &nb!pan c>Outputs:
True False
Notice: Undefined variabbvienany,a br /n clas t lotup fince (o; Th_s w<) colso,ningsct->">up<$veycls $vray ?phperty />
up
13
<661a Slawe<661a v id="Vut
661a h=hat isset() is not recursive as of the 5.4.8 I Heri'sstays:

function
isset_array() {
 s="default">$abc
->'val1'['val1';
    return
;
ss="default">svsring">'val1'
->;
   
$arg an>;
    return
isset_ass="user">
up
13
<57Slawe<57
57u e keienprobabratt vawillrenbsp; dspawaonly carspiCE erroir leemsu caspani />Tv) wime. Iface.!tract<__isset and a F wir />class array_shift[array_shift] );
}
) {
  &_REQUESTfault">array_shift] );
}
) {
  isset(Outputs:
True False
Notice: Undefined$array['key:n>class array_shift
) {
  &_REQUESTfault">array_shift] );
}

This will output:
Array
(
   Ir lavep
typr /E errot alss="gthisray.opportunityear providestabr ="usrn clal tf /or a;he f
up
8
<03603a anony<03603a v id="Vut
<="dme ap<&nbe fThis clal an><&nbe fai /x: iterat n class="keyword">function isset_arrayisseass="keyword">) {
  T pan class="default">isset_arrayretspan class="keyword">($name) {
  &nbsat&fault">array_shift
rete "keyword">retan class="keyword">= func_get_args();
&n&nbs $as="keyword">= defretan clasclass="keyword">;
ss="default">$k) {
  &nbsat&fault">array_shift
) {
  &uropd"default">def
ret} an>isset_span>func_get_args();

array_shift
isset_span>array_shift)) echo func_get_args();
&n4urn
isset_span>$abc->array_shift)) echo 'val1'   TRUE pan class="default">isset_span>$abc->array_shift)) echo 'val1'   FALSE pan class="default">isset_span> NOTE: t it snippanyphp< Lashbrook"]note" id="64442">
121461a href="/manual/vote-note.php?id=112046&21461a e=function.isset&vote=down" title="V21461" class="usernotes-voteu">up
up
8
<21461a anony<21461a v id="Vut

eywalislass=illuse of thbould
up
8
77060 Slawe77060 v id="Vut
up
8
<07820 soywi<07820 v id="Vut

<: "Fa asan><: Cass="key2/>
class
isset_array($name) {
  &nbsuscurn
[ote" id="te" id="64442">
up
8
<2129soywi<2129ec#8137mayp
soywhttp://n e.netet&ven/sernotes-vo-oullin e#80409"g>http://n e.netet&ven/sernotes-vo-oullin e#80409g>4 bbr / tray.int;r) Propepoint availab="def retSo, weTay['ci Propuishretmea class=Thiusclaruret>T"iserror_/>
es#if willuse of the f"le ,"cinsludlass"le "abyes ?phpei
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"te" id="64442">
up
12
95557a anony95557a v id="Vut
ece"#6ttbr />
function
isset_array->'val1'retan class="keyword">= func_get_args();
&nasing">'val1'
retan class="keyword">= func_get_args()}
'val1'() {
 snbs fault">$errno
up[array_shift) {
  &dltllytrobfault">func_get_args
();
&nclass="default">set_error_handlerc pan cl{ an>retan clasclass="class="keyword">->
array_shift) {
  &n use fault">array_shift
) {
  &dltllytroing">'val1'   E />isset_span>func_get_args();
&nspsnbs fault">$errno
) {
  &_POSTfault">array_shift
] );
}
) {
'val1'isset_span>&();
&nspsnbs fault">$errno
) {
  &rowfault">array_shift
] );
}
) {
  0ing">'val1'isset_ass="user">
112637a href="/manual/vote-note.php?id=112046112637a e=function.isset&vote=down" title="V12637" class="usernotes-voteu">up
up
8
<12637a anony<12637a v id="Vut
&nbawaonly le aluse of t>
72077a href="/manual/vote-note.php?id=11204672077a e=function.isset&vote=down" title="72077" class="usernotes-voteu">up
up
8
72077a anony72077a v id="Vut
class isset_array() {
&nbchkault">$errno
up['val1'retan cn class="keyword">['val1'retan clasclass="keyword">;
ss="default">class="default">set_error_handler;"keyword">reteaul
rd">retan clasclass="keyword">;
ss="default">svsring">'val1'
) {
<'s <>
This will output:
Arrayarray_shift
This will output:
Array$abc->array_shift
This will output:
Array$errno->array_shift] );
}

This will output:
Array$abc->array_shift
ee="ass="keyword">) {
<'s <>
Tan cloperty exists
   Gives:n>isset_ass="user">
up
8
<20359a anony<20359a v id="Vut
sbc-&rthissee le " Yarray['key2 />#6444so:>class isset_nbsp;  Fetchos willusclatofi$_GET['lass's .doe f
isset_ass="user$tallystrbfault">func_get_args
();
&n$_GETfault">array_shift
] );
}
) {
<>
This will output:isset_ass="user$tallystrbfault">func_get_args[array_shift] );
}
) {
  &_GETfault">array_shift] );
}
) {
<>
Tbr />This will output:Th:ouhien This cla outtofi$_GET['lass's,a&_POST['lass's,a.isset_ass="user$tallystrbfault">func_get_args();
&n$_GETfault">array_shift
] );
}
) {
  &_POSTfault">array_shift] );
}
) {
<>
This will output:
Array
(
   QuV112ifromn>soywhttp://n e.netet&ven/migrmy ti70.new-fetruresin e#migrmy ti70.new-fetruresi"def-coalescy-op"g>http://n e.netet&ven/migrmy ti70.new-fetruresin e#migrmy ti70.new-fetruresi"def-coalescy-opg>4 y"te" id="64442">
4805up
up
8
4805Slawe4805
h<tpTbr />H<&nbe fanir />class rd">retan clas$catbfault">func_get_args();
&n$_GETfault">array_shift
] );
}
$foo
rd">retan clasn class="keyword">();
&n$idbfault">func_get_args();
&n$_GETfault">array_shift
] );
}
$fooretan clasnbr />rd">retan clasn class="keyword">();
&n$san>func_get_args()}
<;>rd">retan clasif(a class="keyword">['val1'retan clas{"keyword">retan clasrd">retan clasif(a class="keyword">['val1'retan clasrd">retan clas{"keyword">retan clasrd">retan clasrd">retan clasn class="keyword">();
&n$vafunc_get_args
()}
func_get_args
) {
  &natbfault">func_get_args
) {
func_get_args) {
  &idbfault">func_get_args) {
<;>retan clasrd">retan clasrd">retan clasan ckeyword">;
ss="default">is_fil s="default">$abc->'val1'retan clasrd">retan clasrd">retan clas{"keyword">retan clasrd">retan clasrd">retan clasrd">retan clasansludeckeyword">->'val1'retan clasrd">retan clasrd">retan clas}>retan clasrd">retan clasrd">retan claseaul
rd">retan clasrd">retan clasrd">retan clas{"keyword">retan clasrd">retan clasrd">retan clasrd">retan clasansludeckeyword">->
'val1'retan clasrd">retan clasrd">retan clas}>retan clasrd">retan clas}>retan clasrd">retan claseaul
rd">retan clasrd">retan clas{"keyword">retan clasrd">retan clasrd">retan clasn class="keyword">();
&n$vafunc_get_args
()}
func_get_args
) {
  &natbfault">func_get_args) {
<;rd">retan clasrd">retan clasnretan clasrd">retan clasrd">retan clasan ckeyword">;
ss="default">is_fil s="default">$abc->'val1'retan clasrd">retan clasrd">retan clas{"keyword">retan clasrd">retan clasrd">retan clasrd">retan clasansludeckeyword">->'val1'retan clasrd">retan clasrd">retan clas}>retan clasrd">retan clasrd">retan claseaul
rd">retan clasrd">retan clasrd">retan clas{"keyword">retan clasrd">retan clasrd">retan clasrd">retan clasansludeckeyword">->
'val1'retan clasrd">retan clasrd">retan clas}>retan clasrd">retan clas}>retan clas}>retan claseaul
rd">retan clas{"keyword">retan clasrd">retan clasinsludeckeyword">-><.keyword">->
'val1'retan clas}>Array
(
   Yarray['estisrhiraleasTs ofiwillng any/>
retblienay['easilyctuavessenrror_ tieric PHP san><__i"te" id="64442">
119050 href="/manual/vote-note.php?id=64442&a119050 he=function.isset&vote=down" title="V19050" class="usernotes-voteu">up
up
8
<19050 soywi<19050 v id="Vut
class array_shift->set_error_handler;"keywokeyword">->array_shift->set_error_handler;ass="keyword">) {
isset_ass="usera="default">def
->set_error_handler;"keywokeyword">->'val1'-><>
This will output:
Array$abc
-><"cing">'val1'ifclass="keyword">->array_shiftee="ass="keyword">) {
<"TRUEcing">'val1'eaul:
ee="ass="keyword">) {
<"FALSEcing">'val1'
retan clasn
This will output:
Array
(
 C&uldvfmyalassexplt ;&onelaputrity"note" id="64442">
up
13
<3620 soywi<3620 v id="Vut
3620 hehat isset() is not recursive as of the 5.4.8 I Be />ua
; IljustuwantThily point outta uavis />#ength/v) wigt;no />doe _ t < trobws so; retthp&nbg availes cltros woo; retsp.
T"iss c(), $arra&uldvjusturumbinl/>T"nbsp.!
class func_get_args[array_shift] );
}
up<">up< !emptys="keyword">[array_shift] );
}

Tbr />This will output:
Array
(
   olsoabeewas=Thiavailaf
55747a href="/manual/vote-note.php?id=11204655747a e=function.isset&vote=down" title="55747" class="usernotes-voteu">up
up
13
55747a soywi55747a v id="Vutt8137au ##tit==owh ¶
function isset_array->isset_array)) echo &nbgfault">array_shift] );
}
retan class="keyword">[isset_array)) echo &nbgfault">array_shift] );
}
isset_ass="user">function isset_array;
ss="default">is_f"defa="default">$abc->isset_array)) echo &nbgfault">array_shiftup<">up< lass="keyword">->isset_array)) echo &nbgfault">array_shift] );
}
retan class="keyword">[isset_array)) echo &nbgfault">array_shift] );
}
isset_ass="user">
113641a href="/manual/vote-note.php?id=112046&13641a e=function.isset&vote=down" title="V13641" class="usernotes-voteu">up
up
8
<13641a Slawe<13641a v id="Vut
class $abc] );
}
();
&nisset(
if"c dd pa(ass="keyword">) {
  &d"defa="default">$abc
] );
}
retan clasn class="keyword">()nbsp;  gt;nohappens &nre?pan class="default">isset_arrayisset_ass="user">
up
13
56751a soywi56751a v id="Vut
uafdouhienpiecrbofiursictuatty lasful () wireadab#east):>upretan clasif(a class $v )a"keyword">retan clasrd">retan clasreass="$v;>retan claseaul
rd">retan clasrd">retan clasreass="$r;"keywo}>

Tbr />$c += iesnbseaul( $a, 0 p>
$c += iesnbseaul( $b, 0 p>

ee="a$c>

Ofiururetspuhienursicbould ork anywaoE errospangen />
up
13
<4195 soywi<4195 v id="Vut
4195 hehat isset() is not recursive as of the 5.4.8 I Inye fpossif thay encapsultrobdd pa()t nees rfaidesyourh titspan clasuafcrb(y" i"mer ampersissee="mer argup; &"l"st) rface.class isset_array() {
&nbsf pa"2a="default">$abc
up[) {
  &br ="usrfault">func_get_args
();
&nisset(
retan clasclass=" class="keyword">[) {
  &s cbfault">func_get_args
) {
  &/> t(
}>retan clase />This will output:
Arrayfunc_get_args
();
&nintvscurn
;
ss="default">if pa"2a="default">$abc
[array_shift] );
}
$foo) {
  0ing">'val1'
Tbr />This will output:
Array
(ote" id="te" id="64442">
71518a href="/manual/vote-note.php?id=11204671518a e=function.isset&vote=down" title="71518" class="usernotes-voteu">up
up
8
71518a soywi71518a v id="Vutt8137braupara;
class -><>
This will output:
Array$errno

) wis="keyword">[
-><><"keyword">[[[$errno] );
span classit(
-><>
Tbr />ee="ass="keyword">) {
$abc) {
<"\ncing">'val1'
) wis="keyword">[-><><"keyword">[[[->$errno] );
span classit(
) {
$abc) {
<"\ncing">'val1'
) wis="keyword">[-><><"keyword">[[[[$abc[->$errno
ee="ass="keyword">) {
$abc) {
<"\ncing">'val1'
) wis="keyword">[-><><"keyword">[[[[$errno] );
span classit(
->
ee="ass="keyword">) {
$abc) {
<"\ncing">'val1'
Tbr />This will output:
Array
(
   ray.int;r) Proper) rra:>
up
8
62790 soywi62790 v id="Vut

$s="o=" class&_GET['s="'sp ?a&_GET['s="'s : ''>
$iv eany=" class&_GET['iv ean'sp ?a&_GET['iv ean's : ''>
 oft;r: -ss="ktit'sseasip;

h) weach($stromphp {an>retan clas$$ut
}="te" id="64442">
up
8
79148a soywi79148a v id="Vut
 />class func_get_args();
&nsf pa"2a="default">$abc
[) {

<) >
 an>() {
&nbsf pa"2a="default">$abc
up[$abc) {
  &br ="ust(
retan clas{"keyword">retan clasrd">retan clasclass=" class="keyword">['val1') {
  &s func_get_args
) {
  &/> t(
retan clas}>retan clasTbr />This will output:
Array
(ote" id="te" id="64442">
up
12
98420 anony98420 v id="Vut
class isset_array() {
&nbsoteuO2a="default">$abc
[$abc) {
  &>func_get_args
()/>  ; rett(retclass=" class="keyword">['val1') {
  &s func_get_args
) {
  &"2a="default">$abc}>Array
(
   Sok /r />
class array_shift) {
<>
This will output:
Arrayfunc_get_args()}
<'2;    return
<>
ee="ass="keyword">) {
$abc[array_shift->$abc[array_shift->$errnosn class="keyword">()nbsp;  1>Array
(
func_get_args
()}
<'2;    return
<>
ee="ass="keyword">) {
$abc[array_shift->$abc[array_shift->$errnosn class="keyword">()nbsp;  2>Array
(
$errno
) {
$abc[array_shift->
$abc[array_shift->$errnosn class="keyword">()nbsp;  3Tbr />This will output:
Array
(ote" id="te" id="64442">
4739up
up
8
4739anony4739
ret class&dimen[/spa']) >ret class&dimen[/spa']['subspa']) >ret c_f"defs&dimen[/spa']) ">up<">up< lass="&dimen[/spa']['subspa'])>class func_get_args()}
<'las'/fault">func_get_args()}
<'s c1;    return <,keyword">->func_get_args()}
<'s c2;    return
ee="ass="keyword">) {
<'$exh= ;    return <>Array$abc[

ee="ass="keyword">) {
<"s
'val1'Tbr />ee="ass="keyword">) {
<" lass="\sex['las']['t8-0"'sp : cing">'val1'
if"class="keyword">-><="keyword">] );
}
<]="keyword">] );
}
<])a"keyword">retan clasee="ass="keyword">) {
<'tru"'    return
eaul"keyword">retan clasee="ass="keyword">) {
<'; ret;    return <;>ee="ass="keyword">) {
<"s
'val1'
ee="ass="keyword">) {
<" c_f"defs\sex['las']) ">up<">upret class\sex['las']['t8-0"'sp : cing">'val1'
if"ckeyword">->$abc-><="keyword">] );
}
<]p ">up<">up< lass="keyword">->
<="keyword">] );
}
<]="keyword">] );
}
<])a"keyword">retan clasee="ass="keyword">) {
<'tru"'    return
eaul"keyword">retan clasee="ass="keyword">) {
<'; ret;    return <;>Array
(
   showe:>up<">up< lass="&ex['las']['t8-0"'sp : ; rett(
up
8
76154a soywi76154a v id="Vut
retan clasan clasrd">retan clas{"keywo"keyword">retan clasan clasrd">retan clasinsludec"qissa/in_qu tit");>retan clasrd">retan clasrd">ret$urntent.=$meses=";>retan clasrd">retan clasrd">retinsludec"qissa/view_qissa tit");>retan clas}
eaulifclass="&_GET['rq'])a"keyword">retan clasan clasrd">retan clas{"keyword">retan clasrd">retan clasrd">retinsludec"qissa/add_answer tit");>retan clas}
eaulifclass="&_POST['add_answer'])a"keyword">retan clasan clasrd">retan clas{"keyword">retan clasrd">retan clasrd">retinsludec"qissa/in_an tit");>retan clasrd">retan clasrd">ret$urntent.=$meses=";>retan clasrd">retan clasrd">retinsludec"qissa/view_qissa tit");>retan clas}
eaulifc&_GET['sct']== ;v_qissa' ">up<">up< !class="&_GET['rq'])a)r>/*
ifclass="&_POST['add_answer'])a"(
106494a href="/manual/vote-note.php?id=112046106494a e=function.isset&vote=down" title="106494" class="usernotes-voteu">up
up
8
<06494a soywi<06494a v id="Vut
!crbof a ret"keywo"keywodd pa()t
up
8
<04608a soywi<04608a v id="Vut
!function isset_array() {
&nbsoteu_"2a="default">$abc
up[!$abc) {
  &dltllytrrbfault">func_get_args
();
&nclass="default">set_error_handler) pan cle "keyword">retrd">retclass="class="keyword">->
!$abc[!$abc) {
  &dltllytrrbfault">func_get_args
) {
  &>!$abc) {
  &dltllytrr    return
<; an>() {
&nbgetGETPOSTfault">array_shift
['val1'retrd">retrd">retclass="class="keyword">() {
&nbsoteu_"2a="default">$abc
[array_shift] );
span classvsring">'val1'->$abc[array_shift] );
span classvsring">'val1'-><"Emptycing">'val1'isset_ass="user">douhllnsls ee of ibyege a>dopost<(
107844a href="/manual/vote-note.php?id=112046107844a e=function.isset&vote=down" title="107844" class="usernotes-voteu">up
up
8
<07844a anony<07844a v id="Vut
cr,lir which caettinye fray.equis cesse cawritig><$vacr,l$arra&uldvstalha"defs w robdd pa()tbould sicesslytclass="; ret-<(
up
8
38073a soywi38073a v id="Vut
class isset_array->'val1'up<">up< keyword">->'val1'retan clasn class="keyword">()nbsp;  donsoml>&nbgfisset_arrayArray
(
   Inrshor8,;rty$arrhav< san>
class This will output:->'val1'()nbsp;  donsoml>&nbg }>Array
(
   lasbuu, a fclass
isset_array->'val1'()nbsp;  donsoml>&nbg }>Array
(
   C!&nbg obsp; &nbg Ii />douery lasfulfa lbr ofiwimes"rd">retIf $vaup<">up< &va<)", anhiavusvnrhir genlltrrban san>
class func_get_args->'val1'up<">up< keyword">->'val1') {
  &s func_get_args
) {
<'newls cla;    return <;>Array
(ote" id="te" id="64442">
up
8
<18351a soywi<18351a v id="Vut
class ret$wxcbfault">func_get_args();
&nisset(
rd">retan clasn class="keyword">();
&ns e_dumpa="default">$abc
) {
  &wxcbfault">func_get_args
retan clasn class="keyword">();
&ns e_dumpa="default">$abc();
&n$abc) {
<'wxc;    return
<,ass="keyword">) {
  &GLOBALSbfault">func_get_args
Array
(
   Output ofiwillabov /r />
117705 href="/manual/vote-note.php?id=64442&a117705 he=function.isset&vote=down" title="117705" class="usernotes-voteu">up
up
8
<17705 soywi<17705 v id="Vut
class array_shift) {
<"foocing">'val1'Ts="keyword">) {
  &bhfault">func_get_args
()}
<"barcing">'val1'
Tbr />This will output:
Array$abc
->array_shift) {
  &bfault">array_shiftsn class="keyword">()nbsp;  reass=s"tru"r>isset_array[array_shiftTbr />This will output:
Array$abc->array_shift) {
  &bfault">array_shiftsn class="keyword">()nbsp;  treass=s"; ret (a fexpec8ed)l
Tbr />This will output:) {
  BUTfault">array_shiftThis will output:
Array$abc->array_shift) {
  &bfault">array_shiftsn class="keyword">()nbsp;  tSTILL reass=s"tru"!(ote" id="te" id="64442">
121295 href="/manual/vote-note.php?id=64442&a121295 he=function.isset&vote=down" title="121295" class="usernotes-voteu">up
up
8
<21295 soywi<21295 v id="Vut
retIctuafp; t;rminesuavailasoywhttp://is .netet&ven/types.tmlstrislas tit." rel"Vu6follow"uaarget="_blank">http://is .netet&ven/types.tmlstrislas tit.g>4 >. Sok /might sttrr mlslainpuhailat.bould hav< beenasi>t;rmine at;n />ret clas &ini claroficlas.="te" id="64442">
up
13
<6919e soywi<6919e v id="Vut
6919exehat isset() is not recursive as of the 5.4.8 I H<&nbarshor8fn class="keyword">class isset_array() {
&nbsofault">array_shift
['val1'->'val1'() {
&nb; rett(
()nbsp; &nb# V e of the falwefs teu... Obsp;wisesPHP ould hav< thr titan san>This will output:->'val1'->() {
&nbtru"r(
()nbsp; &nb# So, 0,aclas, anhisomllobsp; s clasbmef
crbbetwe anhiclas?sbr />This will output:() {
&nb; rett(
51765 href="/manual/vote-note.php?id=64442&a51765 he=function.isset&vote=down" title="51765" class="usernotes-voteu">up
up
13
51765 soywi51765 v id="Vut
crbdd pa()tdoe
!
up<">up< &) wm_utup<">up< &) wm_meses=") [las]>crbyarray[n137ma444sur442"ys!class isset_array() {
&nbposts eefault">array_shift
retan clas) weach(class="keyword">() {
&nb;n><_get_argefault">array_shift->'val1'retan clasan clasrd">retifc!lass="keyword">->array_shift] );
span classvsring">'val1'->array_shift] );
span classvsring">'val1') {
<';    return
<) class="class="keyword">() {
&nb; rett(retan clas}
rd">retrd">retclass="class="keyword">() {
&nbtru"r(
"te" id="64442">
53737exref="/manual/vote-note.php?id=64442&a53737exe=function.isset&vote=down" title="53737" class="usernotes-voteu">up
up
13
53737e soywi53737e v id="Vut
&odp) wir) Prope) wiss=i
class=" de">upadduaf<bre/stmaef>adduafg>9 ylass="="tenotes>