asort
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/>
compact
(PHP 4, PHP 5)
compact — Crea una matriz que contiene variables y sus valores
Descripción
compact() toma un número variable de parámetros. Cada uno puede ser tanto una cadena que contiene el nombre de la variable, como una matriz de nombres de variable. La matriz puede contener otras matrices de nombres de variable en su interior; compact() los procesa recursivamente.
Para cada uno de estos, compact() busca una variable con dicho nombre en la tabla de símbolos y la añade a la matriz de salida de modo que el nombre de la variable es la clave y el contenido de ésta es el valor para dicha clave. Para resumir, hace lo contrario de extract(). Devuelve la matriz de salida con las variables añadidas a la misma.
Cualquier cadena que no haya sido definida simplemente se evitará.
Note: Gotcha A causa de que Variables variables no puede ser usada con las Superglobal arrays de PHP dentro de funciones, las matrices Superglobal no pueden ser pasadas a compact().
Example #1 Ejemplo de compact()
<?php
$ciudad = "San Francisco";
$estado = "CA";
$evento = "SIGGRAPH";
$location_vars = array ("ciudad", "estado");
$resultado = compact ("evento", "nada_aqui", $location_vars);
?>
Tras esto, $resultado
Array ( [event] => SIGGRAPH [city] => San Francisco [state] => CA )
Vea también: extract().
add a note
User Contributed Notescompact
packard_bell_nec at hotmail dot com
31-Jan-2008 06:46
31-Jan-2008 06:46
M Spreij
24-May-2007 03:10
24-May-2007 03:10
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
)
mijllirg at wearethedotin dot com
17-Nov-2005 08:38
17-Nov-2005 08:38
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...
hericklr at gmail dot com
13-Jun-2005 05:43
13-Jun-2005 05:43
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);
}
?>
pillepop2003 at yahoo dot de
22-Nov-2004 09:26
22-Nov-2004 09:26
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