Converting Between Arrays and Variables
PHP provides two functions, extract( )
and compact( )
, that convert between arrays and
variables. The names of the variables correspond to keys in the array,
and the values of the variables become the values in the array. For
instance, this array:
$person = array('name' => 'Fred', 'age' => 35, 'wife' => 'Betty');
can be converted to, or built from, these variables:
$name = 'Fred'; $age = 35; $wife = 'Betty';
Creating Variables from an Array
The extract( )
function
automatically creates local variables from an array. The indices of
the array elements are the variable names:
extract($person); // $name, $age, and $wife are now set
Tip
If a variable created by the extraction has the same name as an existing one, the extracted variable overwrites the existing variable.
You can modify extract( )
’s
behavior by passing a second argument. Appendix A describes the possible
values for this second argument. The most useful value is EXTR_PREFIX_ALL
, which indicates that the
third argument to extract( )
is a
prefix for the variable names that are created. This helps ensure that
you create unique variable names when you use extract( )
. It is good PHP style to always
use EXTR_PREFIX_ALL
, as shown
here:
$shape = "round"; $array = array("cover" => "bird", "shape" => "rectangular"); extract($array, EXTR_PREFIX_ALL, "book"); echo "Cover: $book_cover, Book Shape: $book_shape, Shape: $shape"; Cover: bird, Book Shape: rectangular, Shape: round
Creating an Array from ...
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