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 — Crea un array contenente variabili e il loro valore
Descrizione
compact() accetta un numero variabile di parametri. Ogni parametro può essere una stringa contenente il nome della variabile, o un array di nomi di variabile. L'array può contenere altri array di nomi di variabile; compact() se ne occupa in modo ricorsivo.
Per ognuno di questi, compact() cerca la variabile con quel nome nella tabella dei simboli corrente, e la aggiunge all'array di output in modo tale che il nome della variabile diventi la chiave e i contenuti della variabile diventino il valore associato a quella chiave. In breve, compact() è l'opposto di extract(). Restituisce l'array di output con tutte le variabili aggiunte a quest'ultimo.
Qualsiasi stringa non valorizzata verrà semplicemente ignorata.
Nota: Gotcha
Dal momento che le variabili variabili non posso essere utilizzate con gli array Superglobal di PHP nelle funzioni, gli array Superglobal non possono essere passati alla funzione compact().
Example #1 esempio di compact()
<?php
$citta = "Milano";
$provincia = "MI";
$evento = "SMAU";
$var_luoghi = array("citta", "provincia");
$risultato = compact("evento", "niente", $var_luoghi);
?>
In questo modo, $risultato sarà:
Array
(
[event] => SMAU
[citta] => Milano
[provincia] => MI
)
Vedere anche 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.
M Spreij ¶
6 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 ¶
8 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);
}
?>
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/>
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
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).