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
                )

        )
 )