asort
The description says that compact is the opposite of extract() but it is important to understand that it does not completely reverse extract(). In particluar compact() does not unset() the argument variables given to it (and that extract() may have created). If you want the individual variables to be unset after they are combined into an array then you have to do that yourself.
compact
(PHP 4, PHP 5)
compact — Erstellt ein Array mit Variablen und deren Werten
Beschreibung
compact() übernimmt eine variable Anzahl von Parametern. Jeder Parameter kann entweder ein String mit einem Variablennamen, oder ein Array mit Variablennamen sein. Dieses Array kann auch andere Arrays mit Variablennamen enthalten; compact() behandelt sie rekursiv.
Für alle diese sucht compact() nach einer Variablen in der aktuellen Symboltabelle, und fügt diese dem zurückzugebenden Array hinzu, wobei der Variablenname als Schlüssel, und der Inhalt der Variablen als Wert gespeichert wird. Kurz, diese Funktion tut das Gegenteil von extract(). Sie gibt ein Array mit allen Variablen zurück.
Strings, welche nicht gesetzt sind, werden einfach ignoriert.
Hinweis: Achtung
Weil variable Variablen nicht mit PHPs superglobalen Arrays verwendet werden dürfen, können die superglobalen Arrays nicht an compact() übergeben werden.
Beispiel #1 compact()
<?php
$stadt = "San Francisco";
$staat = "CA";
$ereignis = "SIGGRAPH";
$location_vars = array("stadt", "staat");
$result = compact("ereignis", "nichts_hier", $location_vars);
?>
Danach wird $result:
Array
(
[ereignis] => SIGGRAPH
[stadt] => San Francisco
[staat] => CA
)
Siehe auch extract().
add a note
User Contributed Notes
compact - [8 notes]
Robc ¶
2 years ago
tatarynowicz at gmail dot com ¶
2 years ago
Please note that compact() will _not_ issue a warning if the specified variable name is undefined.
packard_bell_nec at hotmail dot com ¶
5 years ago
You can check whether a variable is defined by using array_key_exists()!
First, you may ask that no reserved array (would be called $LOCALS) is predefined in function scope (contrast to reserved array $GLOBALS in global scope. To solve it, you can use compact().
Then, you may ask that why property_exists() cannot be used. This is because no reserved function is predefined to create OBJECT containing variables and their values, and no reserved function is predefined to import variables into the current symbol table from an OBJECT. In addition, property_exists() breaks the naming convention of reserved function.
Finally, I show how to check whether a variable is defined by using array_key_exists():
<?php
function too(){
$roo = array_key_exists('foo', compact('foo'));
echo ($roo?'1':'0').'<br/>';
$foo = null;
$roo = array_key_exists('foo', compact('foo'));
echo ($roo?'1':'0').'<br/>';
}
too();
?>
The output will be:
0<br/>
1<br/>
M Spreij ¶
5 years ago
Can also handy for debugging, to quickly show a bunch of variables and their values:
<?php
print_r(compact(explode(' ', 'count acw cols coldepth')));
?>
gives
Array
(
[count] => 70
[acw] => 9
[cols] => 7
[coldepth] => 10
)
hericklr at gmail dot com ¶
7 years ago
The compact function doesn't work inside the classes or functions.
I think its escope is local...
Above it is a code to help about it.
Comments & Suggestions are welcome.
PS: Sorry for my poor english...
<?php
function x_compact()
{ if(func_num_args()==0)
{ return false; }
$m=array();
function attach($val)
{ global $m;
if((!is_numeric($val)) && array_key_exists($val,$GLOBALS))
{ $m[$val]=$GLOBALS[$val];}
}
function sub($par)
{ global $m;
if(is_array($par))
{ foreach($par as $cel)
{ if(is_array($cel))
{ sub($cel); }
else
{ attach($cel); }
}
}
else
{ attach($par); }
return $m;
}
for($i=0;$i<func_num_args();$i++)
{ $arg=func_get_arg($i);
sub($arg);
}
return sub($arg);
}
?>
mijllirg at wearethedotin dot com ¶
7 years ago
You might could think of it as ${$var}. So, if you variable is not accessible with the ${$var} it will not working with this function. Examples being inside of function or class where you variable is not present.
<?php
$foo = 'bar';
function blah()
{
// this will no work since the $foo is not in scope
$somthin = compact('foo'); // you get empty array
}
?>
PS: Sorry for my poor english...
piedone at pyrocenter dot hu ¶
2 years ago
A quick way of compacting all local variables:
<?php
$localVariables = compact(array_keys(get_defined_vars()));
?>
This is useful if you want to return all local variables from a function/method or you want to pass all local variables to one. A valid example would be to use this with application hooks/events (if you want the called hook to be able to modify everything in the caller), but otherwise use with care (as methods should be used through their declared interface).
pillepop2003 at yahoo dot de ¶
8 years ago
Use the following piece of code if you want to insert a value into an array at a path that is extracted from a string.
Example:
You have a syntax like 'a|b|c|d' which represents the array structure, and you want to insert a value X into the array at the position $array['a']['b']['c']['d'] = X.
<?
function array_path_insert(&$array, $path, $value)
{
$path_el = split('\|', $path);
$arr_ref =& $array;
for($i = 0; $i < sizeof($path_el); $i++)
{
$arr_ref =& $arr_ref[$path_el[$i]];
}
$arr_ref = $value;
}
$array['a']['b']['f'] = 4;
$path = 'a|b|d|e';
$value = 'hallo';
array_path_insert($array, $path, $value);
/* var_dump($array) returns:
array(1) {
["a"]=>
&array(1) {
["b"]=>
&array(2) {
["f"]=>
int(4)
["d"]=>
&array(1) {
["e"]=>
string(5) "hallo"
}
}
}
*/
?>
Rock on
Philipp