in_array

end

[edit] Last updated: Fri, 24 May 2013

extract

(PHP 4, PHP 5)

extract — Importe les variables dans la table des symboles

Description

int extract ( array &$var_array [, int $extract_type = EXTR_OVERWRITE [, string $prefix = NULL ]] )

Importe les variables dans la table des symboles.

extract() vérifie chaque clé afin de contrôler si elle a un nom de variable valide. Elle vérifie également les collisions avec des variables existantes dans la table des symboles.

Liste de paramètres

var_array

Un tableau associatif. Cette fonction crée les variables dont les noms sont les index de ce tableau, et leur affecte la valeur associée. Pour chaque paire clé/valeur, extract() crée une variable, avec les paramètres extract_type et prefix.

Vous devez utiliser un tableau associatif. Un tableau indexé numériquement ne produira aucun résultat, à moins que vous n'utilisiez l'option EXTR_PREFIX_ALL ou EXTR_PREFIX_INVALID.

extract_type

Le traitement des collisions est déterminé par extract_type. Ce paramètre peut prendre une des valeurs suivantes :

EXTR_OVERWRITE: Lors d'une collision, réécrire la variable existante.
EXTR_SKIP: Lors d'une collision, ne pas réécrire la variable existante.
EXTR_PREFIX_SAME: Lors d'une collision, ajouter le préfixe prefix, et créer une nouvelle variable.
EXTR_PREFIX_ALL: Ajouter le préfixe prefix pour toutes les variables.
EXTR_PREFIX_INVALID: Préfixer uniquement les variables aux noms invalides ou numériques avec le préfixe prefix.
EXTR_IF_EXISTS: Écrase la variable uniquement si elle existe déjà dans la table des symboles, et, sinon, ne rien faire. Ceci est pratique pour définir une liste de variables valides, puis extraire du tableau les valeurs que vous avez déjà définies grâce à $_REQUEST, par exemple.
EXTR_PREFIX_IF_EXISTS: Ne crée que des variables préfixées, si la version non préfixée de la même variable existe dans la table des symboles courante.
EXTR_REFS: Extrait les variables sous forme de références. Cela signifie que les valeurs des variables importées font toujours référence aux valeurs des variables d'origine dans le paramètre var_array. Vous pouvez utiliser cette option seule, ou bien la combiner avec d'autres options avec l'opérateur OR, dans le paramètre extract_type.

Si extract_type est omis, extract() utilise EXTR_OVERWRITE par défaut.

prefix

Notez que prefix n'est nécessaire que pour les valeurs de extract_type suivantes : EXTR_PREFIX_SAME, EXTR_PREFIX_ALL, EXTR_PREFIX_INVALID ou EXTR_PREFIX_IF_EXISTS. Si le résultat préfixé n'est pas un nom de variable valide, il ne sera pas importé dans la table des symboles. Les préfixes sont automatiquement séparés de l'index du tableau par un caractère de soulignement.

Valeurs de retour

Retourne le nombre de variables importées avec succès dans la table des symboles.

Historique

Version	Description
4.3.0	`EXTR_REFS` a été ajouté.
4.2.0	`EXTR_IF_EXISTS` et `EXTR_PREFIX_IF_EXISTS` ont été ajoutés.
4.0.5	Cette fonction retourne maintenant le nombre de variables extraites. `EXTR_PREFIX_INVALID` a été ajouté. `EXTR_PREFIX_ALL` inclut également les variables numériques.

Exemples

Exemple #1 Exemple avec extract()

Une utilisation possible de la fonction extract() est l'exportation vers la table des symboles de tableaux de variables retournés par wddx_deserialize().


<?php

/* Supposons que $var_array est un tableau retourné par
   wddx_deserialize */

$size = "large";
$var_array = array("color" => "blue",
                   "size"  => "medium",
                   "shape" => "sphere");
extract($var_array, EXTR_PREFIX_SAME, "wddx");

echo "$color, $size, $shape, $wddx_size\n";

?>

L'exemple ci-dessus va afficher :

blue, large, sphere, medium

La variable $size n'a pas été réécrite, car on avait spécifié le paramètre EXTR_PREFIX_SAME, qui a permis la création de $wddx_size. Si EXTR_SKIP avait été utilisée, alors $wddx_size n'aurait pas été créé. Avec EXTR_OVERWRITE, $size aurait pris la valeur "medium", et avec EXTR_PREFIX_ALL, les variables créées seraient $wddx_color, $wddx_size et $wddx_shape.

Notes

Avertissement

N'utilisez pas extract() sur des données inconnues, comme les données utilisateurs (i.e. $_GET, $_FILES, etc.). Si vous le faites, par exemple, pour rendre compatible un vieux code avec register_globals à Off de façon temporaire, assurez-vous d'utiliser l'une des constantes extract_type qui n'écrasent pas les valeurs, comme EXTR_SKIP. Sachez aussi que vous devez maintenant extraire dans le même ordre que celui défini dans variables_order du php.ini.

Note:
Si vous avez la directive register_globals d'activée et que vous utilisez la fonction extract() sur les variables $_FILES et que vous spécifiez la constante EXTR_SKIP, vous pourriez être surpris du résultat.

Avertissement
Cette façon de faire n'est pas recommandée et est uniquement documentée ici pour bien comprendre le comportement. L'utilisation de la directive register_globals est obsolète et appeler la fonction extract() sur des données partagées comme les variables $_FILES est, comme mentionné ci-dessus, un risque potentiel pour la sécurité. Si vous rencontrez ce problème, cela signifie que vous avez écrit votre code de la mauvaise manière pour au moins 2 raisons.

<?php /* Supposez que $testfile est le nom d'un champ de téléchargement de fichier et que register_globals est actif. */ var_dump($testfile); extract($_FILES, EXTR_SKIP); var_dump($testfile); var_dump($testfile['tmp_name']); ?>

Vous vous attendez à voir quelque chose comme :
string(14) "/tmp/phpgCCPX8"
array(5) {
  ["name"]=>
  string(10) "somefile.txt"
  ["type"]=>
  string(24) "application/octet-stream"
  ["tmp_name"]=>
  string(14) "/tmp/phpgCCPX8"
  ["error"]=>
  int(0)
  ["size"]=>
  int(4208)
}
string(14) "/tmp/phpgCCPX8"
Cependant, vous devriez plutôt voir quelque comme :
string(14) "/tmp/phpgCCPX8"
string(14) "/tmp/phpgCCPX8"
string(1) "/"
Ceci est dû au fait que, depuis que la directive register_globals est active, la variable $testfile existe déjà dans le scope global lorsque la fonction extract() est appelée. Et vû que la constante EXTR_SKIP est spécifiée, la variable $testfile n'est pas écrasée avec le contenu du tableau $_FILES, aussi, la variable $testfile reste une chaîne de caractères. Parceque les chaînes de caractères peuvent être accédées en utilisant la syntaxe des tableaux et que la chaîne de caractères non-numérique tmp_name est interprétée comme 0, PHP voit $testfile['tmp_name'] comme $testfile[0].

Voir aussi

compact() - Crée un tableau à partir de variables et de leur valeur
list() - Assigne des variables comme si elles étaient un tableau

in_array

end

[edit] Last updated: Fri, 24 May 2013

add a note User Contributed Notes extract - [25 notes]

down

moslehi<atsign>gmail<d0t>c0m ¶

7 years ago


Experimentally I found that calling extract() also shows the number of keys if the key is set and is not numeric ! Maybe there was a better definition than mine  . Please have a look to this scripts :



<?PHP 

$var["i"] = "a";

$var["j"] = "b";

$var["k"] = 1;

echo extract($var); // returns 3

?>



<?PHP 

$var2["i"] = "a";

$var2[2] = "b";

$var2[] = 1;

echo extract($var2); // returns 1

?>



(Arash Moslehi)

down

Adam Monsen <adamm at wazamatta dot com> ¶

8 years ago


As shown in the example, if your 'prefix' is used, a single underscore is added to the name of the extracted variable. Meaning, a prefix of 'p' becomes a prefix of 'p_', so 'blarg' prefixed would be 'p_blarg'.



If you're not sure what variables you've created through extraction, you can call get_defined_vars() to see all defined variables in the current scope.

down

Robc ¶

1 year ago


When extracting from a row after a database query using for example:



$row = mysql_fetch_array($result, MYSQL_ASSOC)

extract($row);



I find that the resultant variables may not match the variable type in the database.  In particular I have found integers in the database may gettype() to string on the extracted variable.

down

Dutchdavey ¶

6 years ago


I would draw your attention to the user note at the very end of this page regarding PREFIXES. The user points out that php adds a '_' to your prefixes.

down

ktwombley at gmail dot com ¶

6 years ago


It's really easy to open gaping security holes using extract() on $_REQUEST, $_GET, etc. You have to be really sure of what you're doing, and use the proper flags on extract() to avoid clobbering important variables.



For instance, the submission by kake26 at gmail dot com will not only perfectly emulate register globals (that's bad), but it'll store it in a database and recall the same variables every time the script runs (essentially allowing an attacker to attack your script every time it runs via one attack). Oops!



To fix it, you'd have to get creative with flags. Maybe you could use EXTR_PREFIX_ALL instead of EXTR_OVERWRITE, for example. Of course, you should also sanitize the form elements to ensure there's no php code in them, and also to make sure any very important variables aren't in the form data. (like the classic $is_admin = true attack)

down

nicolas zeh ¶

7 years ago


This function provides exactly the same functionality as extract except that a parameter was added defining the extract target.

This function can be used if your PHP installation does not support the required Flags or more important if you would like to extract arrays to another destination as to $GLOBALS, i.e. other arrays or objects.

The only difference to extract is that extract_to moves the array pointer of $arr to the end as $arr is passed by reference to support the EXTR_REFS flag.



<?php

    if( !defined('EXTR_PREFIX_ALL') ) define('EXTR_PREFIX_ALL', 3);

    if( !defined('EXTR_PREFIX_INVALID') ) define('EXTR_PREFIX_INVALID', 4);

    if( !defined('EXTR_IF_EXISTS') ) define('EXTR_IF_EXISTS', 5);

    if( !defined('EXTR_PREFIX_IF_EXISTS') ) define('EXTR_PREFIX_IF_EXISTS', 6);

    if( !defined('EXTR_REFS') ) define('EXTR_REFS', 256);

    

    

    function extract_to( &$arr, &$to, $type=EXTR_OVERWRITE, $prefix=false ){

        

        if( !is_array( $arr ) ) return trigger_error("extract_to(): First argument should be an array", E_USER_WARNING );

        

        if( is_array( $to ) ) $t=0;

        else if( is_object( $to ) ) $t=1;

        else return trigger_error("extract_to(): Second argument should be an array or object", E_USER_WARNING );

        

        if( $type==EXTR_PREFIX_SAME || $type==EXTR_PREFIX_ALL || $type==EXTR_PREFIX_INVALID || $type==EXTR_PREFIX_IF_EXISTS )

            if( $prefix===false ) return trigger_error("extract_to(): Prefix expected to be specified", E_USER_WARNING ); 

            else $prefix .= '_';

        

        $i=0;

        foreach( $arr as $key=>$val ){

            

            $nkey = $key;

            $isset = $t==1 ? isset( $to[$key] ) : isset( $to->$key );

            

            if( ( $type==EXTR_SKIP && $isset ) 

                || ( $type==EXTR_IF_EXISTS && !$isset ) )

                    continue;

            

            else if( ( $type==EXTR_PREFIX_SAME && $isset )

                || ( $type==EXTR_PREFIX_ALL )

                || ( $type==EXTR_PREFIX_INVALID && !preg_match( '#^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$#', $key ) ) )

                    $nkey = $prefix.$key;

                    

            else if( $type==EXTR_PREFIX_IF_EXISTS )

                if( $isset ) $nkey = $prefix.$key;

                else continue;



            if( !preg_match( '#^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$#', $nkey ) ) continue;

            

            if( $t==1 )

                if( $type & EXTR_REFS ) $to->$nkey = &$arr[$key];

                else $to->$nkey = $val;

            else 

                if( $type & EXTR_REFS ) $to[$nkey] = &$arr[$key];

                else $to[$nkey] = $val;

            

            $i++;

        }

        

        return $i;

    }

    

    // e.g.:

    extract_to( $myarray, $myobject, EXTR_IF_EXISTS );

?>

down

Rodrigo ¶

2 years ago


Here's a way to use extract in $_FILES arrays without using register_gloabals on.



I started to use extract a few weeks ago, and my codes hasn't been so clean since then. The use of the arrays $_POST and $_GET is ok, but one missed doublequote causes a lot of trouble. 



Besides I teach PHP in a school, and this function has made my examples easier.



<?php

if(isset($_FILES["file"])){

    extract($_FILES);

    extract($file);

    echo $name."<br>";

    echo $tmp_name."<br>";

    echo $size."<br>";

}

?>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<title>Documento sin t&iacute;tulo</title>

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">

</head>



<body>

<form action="" method="post" enctype="multipart/form-data" name="form1">

  <p>

    <input type="file" name="file">

</p>

  <p>

    <input type="submit" name="Submit" value="Enviar">

</p>

</form>

</body>

</html>



Hope this can help anyone.

down

danbettles at yahoo dot co dot uk ¶

3 years ago


When using EXTR_PREFIX_ALL - and probably all the other EXTR_PREFIX_* constants - and a numerically-indexed array, extract() will add an underscore ("_") between the prefix and the index.



<?php



extract(array('foo', 'bar'), EXTR_PREFIX_ALL, 'var');



print_r(get_defined_vars());  // Reveals $var_0 = 'foo' and $var_1 = 'bar'

?>

down

benjaminATwebbutvecklarnaDOTse ¶

5 years ago


Re: anon at anon dot org, about extract() and null values



Personally I've found use extracting multiple resultsets from db where the latter would overwrite the previous when a variable is not null ( and optionally if its not >0 )



It would be useful if $extract_type was extended on top of these two:



EXTR_OVERWRITE

EXTR_SKIP



with something like this:



EXTR_OVERWRITE_NULL 

 - If there is a collision, overwrite the existing variable if it is null 



EXTR_OVERWRITE_0

 - Same thing but == 0 or null



EXTR_SKIP_NULL

 - If there is a collision, skip the new variable if the existing is not null



EXTR_SKIP_0

 - Same thing but == 0 or null



Those ought to cover a few good cases that aren't covered now.

down

anon at anon dot org ¶

7 years ago


A warning about extract() and null values.



This might be an actual Zend2 Engine bug, but it's bad programming practice, so I'm sharing it here instead.



I often work in envrionments where E_STRICT (which would prevent errors like this) isn't on, and I don't have access to change it. I also use a very simple template class that in a nutshell works like this:



$t = new Template('somefile.php');

$t->title = $title;

$t->body = $body;

$t->display();



display() more or less looks like this:



function display(){

    extract(get_object_vars($this),EXTR_REFS);

    ob_start(); include $this->templateFileName;

    return ob_get_clean();

}



If any of the assigned values are null (let's say that in this case $title wasn't initialized above) it causes the engine to do all sorts of incredibly whacky stuff like certifiably lose track of variables in an incredibly inconsistent way. I traced the problem down to the fact that it's using the EXTR_REFS flag. I assume that in PHP's internal variable storage or reference counting mechanism, that trying to extract null references makes it lose track or count of something or rather.



In a nutshell, if you start getting wierd behavior when using extract() make sure that the array or object you are trying to get variables out of doesn't contain null keys or values!

down

kake26 at gmail dot com ¶

8 years ago


The following is a neat use for extract to store and manipulate large amounts of form data from. I basically loop through the $_POST and implode it seperating the key and value pairs by a space. Then store it in a db, the reversing function basically explodes the string to a array. Then converts the indexed array to a associative array then uses extract to seal the deal and make it easily available within a program. My main reason for sharing these are the fact I make some big web applications that store allot of forum data in a DB and these functions make it very easy to quickly and easily store and recall the data. I've contributed it because I spent many hours creating this code and recall going "I wish someone had previously submitted it to the page notes". Would have saved me allot of time and agony and I'm sure I'm not the only person that could really benefit from it, so I decided to share.



<?php

$stack = array();

foreach ($_POST as $key => $value) {

array_push($stack, $key, $value);

}

// store it

$block = implode(" ",$stack); // yeilds a space delimited string

// insert query to store string in DB here, like the one below

$query = "INSERT INTO `sometable` VALUES('".$seluser."','".addslashes($block)."');";

$result = mysql_query($query) or die("Query failed for block insert: " . mysql_error());

// note $seluser in my case is a user ID associated with that block

// in one of my web apps

?>



The nice thing is with the above we can quickly create a string of key and value pairs from the data the script got. Without really caring what their names are. You know how if register globals are on you say $someformvar rather than $_POST["someformvar"]; , basically the code below reads this previous created block returns it to that state. Sort of like presistant register globals.



<?php

// insert query to grab the previously stored string here

$query = "SELECT * FROM `sometable` WHERE `blockid` = '".addslashes($bid)."';";

$result = mysql_query($query) or die("Query failed read: " . mysql_error());

$sql = mysql_fetch_array($result, MYSQL_ASSOC);

$array = eplode(" ",$sql["data"]); 

for ($i = 0; $i < sizeof($array); $i+=2) { 

$myassoc[$array[$i]] = isset($array[$i+1])?$array[$i+1]:NULL; 

}

extract($myassoc, EXTR_OVERWRITE);

// now you're key and value pairs from $_POST have been restored

// instead of $_POST

?>

down

-1

darylblake at gmail dot com ¶

2 years ago


Warning: in larger php web applications this is not a good choice. Use of this function will not help maintainability of your code. 





please read php warnings about using this on untrusted data:





<?php


$sql=query("SELECT * FROM contact WHERE contact_id='$invoicedata_clientcontact'");


        if ($tmp=fetch_array($sql))


        {


            extract($tmp);


        }


?>





it will create variables that may overwrite other variables and can cause strange behaviour, advise against using this function if at all possible.

down

FredLawl ¶

13 days ago


It is possible to use this as a way to create public attributes for a class.



<?php

class Foo {



  public function __construct ($array) {



      extract($array, EXTR_REFS);

      foreach ($array as $key => $value) {

          $this->$key = $$key;

          // Do: $this->key = $key; if $key is not a string.

      }



  }



}



$array = array(

    'valueOne'      => 'Test Value 1',

    'valueTwo'      => 'Test Value 2',

    'valueThree'    => 'Test Value 3'

);



$foo = new Foo($array);



// Works

echo $foo->valueOne; // Test Value 1

echo $foo->valueTwo; // Test Value 2



// Does not work!

echo $foo::$valueOne; // Fatal error:  Access to undeclared static property: Test::$valueOne

?>

down

dotslash.lu at gmail.com ¶

26 days ago


You can't extract a numeric indexed array(e.g. non-assoc array).

<?php

$a = array(

  1,

  2

);

extract($a);

var_dump(${1});

?>



result:

PHP Notice:  Undefined variable: 1 in /Users/Lutashi/t.php on line 7



Notice: Undefined variable: 1 in /Users/Lutashi/t.php on line 7

NULL

down

auto493097 at hushmail dot com ¶

3 years ago


I use XDebug with NetbeansIDE to for analyzing and developing PHP Code. When debugging an extract statement no new variables appeared in the variable's list. Although all variables created by extract could be examined by explicit watch items and single variables appeared as soon as an PHP script makes use of them I am not sure weather it is a wrong configuration, a feature or a bug in XDebug.

down

Hayley Watson ¶

5 years ago


Dan O'Donnell's suggestion needs a third requirement to work as described:



c) No other variables are defined - especially variables that contain potentially sensitive information.



Without that condition the difference between extract() and assigning variables by hand (and the resulting security implications) should be obvious.



The only valid security step there is (b) - but you should be doing that anyway.

down

Dan O'Donnell ¶

6 years ago


Following up on ktwombley at gmail dot com's post:



Presumably one easy way of dealing with this security issue is to use the EXTR_IF_EXISTS flag and make sure 



a) your define acceptable input variables beforehand (i.e. as empty variables)

b) Sanitise any user input to avoid unacceptable variable content. 



If you do these two things, then I'm not sure I see the difference between extract($_REQUEST,EXTR_IF_EXISTS); and assigning each of the variables by hand.



I'm not talking here about the idea of storing the variables in a database, just the immediately necessary steps to allow you to use extract on REQUEST arrays with relative safety.

down

owk dot ch199_ph at gadz dot org ¶

7 years ago


And if you want with PHP 5 an easy way to extract $V by reference, try this :

<?php

    foreach ($V as $k => &$v) {

        $$k =& $v;

    }

?>

It can be used to create special kind of "free args" functions that let you choose when you call them the way you send variables, and which ones. They are moreover very fast to call thanks to references :

<?php

    function free_args (&$V) {

        foreach ($V as $k => &$v) {

            $$k =& $v;

        }

        unset ($k);  unset ($v);  unset ($V);



        // be careful that if you need to extract $k, $v or $V variables you should find other names for them in the lines above (ie. $__k, $__v and $__V)

    }



    $huge_text = '...';



    $a = array ('arg1' => 'val1', 'arg2' => &$huge_text); // in this call, only $arg2 will be a true reference in the function

    free_args ($a);

?>

Be warned that you can't write : "<?php free_args (array ('arg1' => 'val1')); ?>" because the array can't be referenced by the function, as it's not yet created when the function starts.

down

Csaba at alum dot mit dot edu ¶

7 years ago


Sometimes you may want to extract only a named subset of the key/value pairs in an array.  This keeps things more orderly and could prevent an unrelated variable from getting clobbered from an errant key.  For example,



$things = 'unsaid';

$REQUEST = array(He=>This, said=>1, my=>is, info=>2, had=>a,

                 very=>3, important=>test, things=>4);

$aVarToExtract = array(my, important, info);

extract (array_intersect_key ($REQUEST, array_flip($aVarToExtract)));



will extract

$my = 'is';

$important = 'test';

$info = 2;



but will leave certain

$things = 'unsaid'



Csaba Gabor from Vienna

NB.  Of course the composite request coming in from a web page is in $_REQUEST.

down

pg dot perfection at gmail dot com ¶

8 years ago


Here is a little example of how an extraction method should look like when it needs to work recursive (work on nested_arrays too)...



Note that this is only an example, it can be done more easily, and more advanced too.



<?php

/**

 * A nested version of the extract () function.

 *

 * @param    array    $array        The array which to extract the variables from

 * @param    int        $type        The type to use to overwrite (follows the same as extract () on PHP 5.0.3

 * @param    string    $prefix        The prefix to be used for a variable when necessary

 */

function extract_nested (&$array, $type = EXTR_OVERWRITE, $prefix = '')

{

    /**

     *  Is the array really an array?

     */

    if (!is_array ($array))

    {

        return trigger_error ('extract_nested (): First argument should be an array', E_USER_WARNING);

    }



    /**

     *  If the prefix is set, check if the prefix matches an acceptable regex pattern 

     * (the one used for variables)

     */

    if (!empty ($prefix) && !preg_match ('#^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$#', $prefix))

    {

        return trigger_error ('extract_nested (): Third argument should start with a letter or an underscore', E_USER_WARNING);

    }



    /**

     * Check if a prefix is necessary. If so and it is empty return an error.

     */

    if (($type == EXTR_PREFIX_SAME || $type == EXTR_PREFIX_ALL || $type == EXTR_PREFIX_IF_EXISTS) && empty ($prefix))

    {

        return trigger_error ('extract_nested (): Prefix expected to be specified', E_USER_WARNING);

    }



    /**

     * Make sure the prefix is oke

     */

    $prefix = $prefix . '_';



    /**

     *  Loop thru the array

     */

    foreach ($array as $key => $val)

    {

        /**

         *  If the key isn't an array extract it as we need to do

         */

        if (!is_array ($array[$key]))

        {

            switch ($type)

            {

                default:

                case EXTR_OVERWRITE:

                    $GLOBALS[$key] = $val;

                break;

                case EXTR_SKIP:

                    $GLOBALS[$key] = isset ($GLOBALS[$key]) ? $GLOBALS[$key] : $val;

                break;

                case EXTR_PREFIX_SAME:

                    if (isset ($GLOBALS[$key]))

                    {

                        $GLOBALS[$prefix . $key] = $val;

                    }

                    else

                    {

                        $GLOBALS[$key] = $val;

                    }

                break;

                case EXTR_PREFIX_ALL:

                    $GLOBALS[$prefix . $key] = $val;

                break;

                case EXTR_PREFIX_INVALID:

                    if (!preg_match ('#^[a-zA-Z_\x7f-\xff]$#', $key{0}))

                    {

                        $GLOBALS[$prefix . $key] = $val;

                    }

                    else

                    {

                        $GLOBALS[$key] = $val;

                    }

                break;

                case EXTR_IF_EXISTS:

                    if (isset ($GLOBALS[$key]))

                    {

                        $GLOBALS[$key] = $val;

                    }

                break;

                case EXTR_PREFIX_IF_EXISTS:

                    if (isset ($GLOBALS[$key]))

                    {

                        $GLOBALS[$prefix . $key] = $val;

                    }

                break;

                case EXTR_REFS:

                    $GLOBALS[$key] =& $array[$key];

                break;

            }

        }

        /**

         *  The key is an array... use the function on that index

         */

        else

        {

            extract_nested ($array[$key], $type, $prefix);

        }

    }

}

?>

down

Michael Newton ¶

8 years ago


They say "If the result is not a valid variable name, it is not imported into the symbol table."



What they should say is that if _any_ of the results have invalid names, _none_ of the variables get extracted.



Under 4.3.10 on Windows 2000, I was pulling some mySQL records, but needed to convert two fields into IP addresses:

<?

extract(mysql_fetch_assoc(mysql_query('SELECT * FROM foo')));

extract(mysql_fetch_assoc(mysql_query('SELECT INET_NTOA(bar) AS bar, INET_NTOA(baz) FROM foo')));

?>



I had forgotten the second AS modifier in the SQL query.  Because it couldn't extract a variable called INET_NTOA(baz) into the symbol table, it didn't do either of them.



(BTW I don't normally stack functions up like that!  Just to make a short example!)

down

Anonymous ¶

8 years ago


To make this perfectly clear (hopefully), an underscore is always added when the string is prefixed.

extract(array("color" => "blue"),EXTR_PREFIX_ALL,'');// note: prefix is empty

is the same as

$color='_blue';

down

Aaron Stone ¶

8 years ago


If you are working porting an older application, and taking the advice above, extracting only _SERVER, _SESSING, _COOKIE, _POST, _GET, you have forgotten to extract _FILES. Putting _FILES last and using EXTR_SKIP doesn't work because the name of the file upload box is already set as a variable containing only the temporary name of the uploaded file from one of the earlier extracts (I haven't tested to see which one specifically, however). A workaround is to put _FILES last and use EXTR_OVERWRITE. This allows extract to replace that temp-name-only variable with the full array of file upload information.

down

-2

Justin Heesemann ¶

2 years ago


This function shows odd behavior when used in class methods and an array key called "this" is being extracted:



<?php

class a {

        protected $foo;

        function b ($r) {

                extract($r);

                var_dump($this);

                //properties still can be acccessed:

                $this->foo = "bling";

                echo $this->foo,"\n";

                // next line would stop the script from compiling

                //$this = "this will raise a fatal error";



        }

}



$a = new a();

$a->b(array("this" => "that"));

?>



prints:

string(4) "that"

bling

down

-2

benjaminATwebbutvecklarnaDOTse ¶

5 years ago


In the meantime, I'm using this:



// extract alternative

# extracts variables where new value is above the threshold or if old value is on or below the threshold (or var is not defined)

# an associative array is obviously the sane thing to pass

#

# I am absolutely certain someone will find obvious problems or errors with this 

# I haven't even tried to compare other values than 0 so if you need to do that and surely finds obvious flaws, 

# please mail me, I'd really like to know. 

# benjaminATwebbutvecklarnaDOTse



// usage example:

# thrextract(mysql_fetch_assoc(mysql_query("SELECT preset_this,preset_that FROM site_preset WHERE ID = $site_id")));

# thrextract(mysql_fetch_assoc(mysql_query("SELECT preset_this,preset_that FROM category_preset WHERE ID = $category_id"))); 



function thrextract($arr,$thr = 0){

    foreach($arr as $key => $var){

        global $$key;

        if($var > $thr or $$key <= $thr) $$key = $var;

    }

}

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