Searching a multidimensional array for objects - php

Question

I have a multidimensional array in PHP and want to be able to search through it and find all values that are objects.
The reason I want to do this is so that when an object is found I can replace it with an array by calling an output() method on it. The output() method uses get_object_vars() to turn itself into an array, which it then returns.
Here's an example which achieves what I want manually (but only with 2 levels of depth):
// First level search...
foreach($array as $k => $v) {
// Check if it's an array.
if (is_array($v)) {
// Second level search...
foreach($v as $k2 => $v2) {
// If it's an object - convert it!
if (is_object($v2)) {
$array[$k][$k2] = $array[$k][$k2]->output();
}
}
}
// If it's an object - convert it!
if (is_object($v)) {
$array[$k] = $array[$k]->output();
}
}

Answer 1

Tim Cooper's answer is wrong because the function must have a parameter that is passed by reference and not by value.
php > class Foo { public function output() { return "this was an object"; } }
php > $a = array( 1 => array( 2 => array( 'foo', 'red', 1, new Foo() ) ) );
php > array_walk_recursive( $a, function( $item, $key ) {
if ( is_object( $item ) ) {
$item = $item->output();
}
} );
php > print_r( $a );
Array
(
[1] => Array
(
[2] => Array
(
[0] => foo
[1] => red
[2] => 1
[3] => Foo Object
(
)
)
)
)
Versus passing by reference:
php > array_walk_recursive( $a, function( &$item, $key ) {
if ( is_object( $item ) ) {
$item = $item->output();
}
} );
php > print_r( $a );
Array
(
[1] => Array
(
[2] => Array
(
[0] => foo
[1] => red
[2] => 1
[3] => this was an object
)
)
)

Answer 2

You just need a recursive function:
function objects_to_arrays_recursive (&$array) {
foreach ($array as &$member) {
if (is_object($member)) {
$member = $member->output();
}
if (is_array($member)) {
objects_to_arrays_recursive($member);
}
}
}
This will call the output() method of every object and store the result in the key that originally held the object.
Caveats:
This will loop the objects once they have been converted and also convert child objects. You may not want to do this, particularly if you have circular references as this would result in an infinte loop. It can be avoided just by changing the 2 ifs into if / elseif.
This does not check whether a given object has an output() method to call. You should probably add an is_a()/instanceof check.
This function takes its argument by reference, which means the input array will be modified. If you need to keep the original array intact, you will need to make a copy of it first.