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
)
(PHP 4, PHP 5, PHP 7, PHP 8)
compact — Crea un array a partir de variables y su valor
Crea un array a partir de variables y su valor.
Para cada uno de los argumentos varname, ...,
compact() busca una variable
con el mismo nombre en la
tabla actual de símbolos, y
la añade al array, de manera que se tenga la relación nombre =>
'valor de variable'. En resumen, es lo contrario de la función
extract().
Nota:
Antes de PHP 7.3, todas las cadenas no definidas eran ignoradas en silencio.
var_namevar_names
compact() acepta diferentes parámetros varname.
Los parámetros pueden ser variables que contienen cadenas,
o un array de cadenas, que puede contener otros arrays de nombres de
variables, que compact() tratará de manera recursiva.
Devuelve el array de salida que contiene todas las variables añadidas.
compact() emite un error de nivel E_WARNING si una
cadena dada hace referencia a una variable no definida.
| Versión | Descripción |
|---|---|
| 8.0.0 |
Si una cadena dada hace referencia a una variable no definida, se emite un error de nivel E_WARNING.
|
| 7.3.0 |
compact() emite ahora un error de nivel E_NOTICE
si una cadena dada hace referencia a una variable no definida. Anteriormente,
estas cadenas eran ignoradas en silencio.
|
Ejemplo #1 Ejemplo con compact()
<?php
$city = "San Francisco";
$state = "CA";
$event = "SIGGRAPH";
$location_vars = array("city", "state");
$result = compact("event", $location_vars);
print_r($result);
?>El resultado del ejemplo sería:
Array
(
[event] => SIGGRAPH
[city] => San Francisco
[state] => CA
)
Nota: Error común
Debido a que las variables variables no deben ser utilizadas con los arrays superglobales en funciones, los arrays Superglobales no deben ser pasados a la función compact().
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
)Consider these two examples. The first as used in the manual, and the second a slight variation of it.
Example #1
<?php
$city = "San Francisco";
$state = "CA";
$event = "SIGGRAPH";
$location_vars = array("city", "state");
$result = compact("event", $location_vars);
print_r($result);
?>
Example #1 above will output:
Array
(
[event] => SIGGRAPH
[city] => San Francisco
[state] => CA
)
Example #2
<?php
$city = "San Francisco";
$state = "CA";
$event = "SIGGRAPH";
$location_vars = array("city", "state");
$result = compact("event", "location_vars");
print_r($result);
?>
Example #2 above will output:
Array
(
[event] => SIGGRAPH
[location_vars] => Array
(
[0] => city
[1] => state
)
)
In the first example, the value of the variable $location_values (which is an array containing city, and state) is passed to compact().
In the second example, the name of the variable $location_vars (i.e without the '$' sign) is passed to compact() as a string. I hope this further clarifies the points made in the manual?So compact('var1', 'var2') is the same as saying array('var1' => $var1, 'var2' => $var2) as long as $var1 and $var2 are set.If you must utilise this knowing that a variable may be unset, then you need to use an alternative method.
So instead of the following:
<?php
$var1 = "lorem";
$var2 = "ipsum";
$result = compact('var1', 'var2', 'unsetvar');
?>
Consider the following:
<?php
$var1 = "lorem";
$var2 = "ipsum";
$result = [];
foreach( ['var1', 'var2', 'unsetvar'] as $attr ) {
if ( isset( $$attr ) ) {
$result[ $attr ] = $$attr;
}
}
?>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.