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 — Crear un array que contiene variables y sus valores
Crea un array que contiene variables y sus valores.
Por cada variable, compact() busca una variable con ese nombre en la tabla de símbolos actual y las añade al array de salida de modo que el nombre de la variable se convierte en la clave y el contenido de la variable se convierte en el valor para esa clave. En pocas palabras, hace lo contrario que extract().
Nota:
Antes de PHP 7.3, cualquier cadena que no esté establecida se omitirá silenciosamente.
varname1compact() toma un número variable de parámetros. Cada parámetro puede ser una cadena que contiene el nombre de la variable, o un array de nombres de variables. El array puede contener otros arrays de nombres de variables dentro de él; compact() los trata recursivamente.
Devuelve un array de salida con todas las variables añadidas a él.
Ejemplo #1 Ejemplo de compact()
<?php
$ciudad = "San Francisco";
$estado = "CA";
$evento = "SIGGRAPH";
$vars_región = array("ciudad", "estado");
$resultado = compact("evento", "nada_aquí", $vars_región);
print_r($resultado);
?>El resultado del ejemplo sería:
Array
(
[evento] => SIGGRAPH
[ciudad] => San Francisco
[estado] => CA
)
Nota: A tener en consideración
Ya que las variables variables no se pueden usar con Arrays Superglobales de PHP dentro de funciones, los arrays Superglobales no pueden ser pasados a 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.