How do I use a recursive array iterator to process a multidimensional array?

Question

I\'m trying to get something like this working:

function posts_formatter (&$posts){
    foreach ($posts as $k => $v){

        if (is_array($v)){

                


        

Answer 1

Ok, here is a quick something for you to figure out:

$data = array(
    'title'    => 'how to work with iterators',
    'posts' => array(
        array(
        'title'  => 'introduction to iterators',
        'email'  => 'JohnDoe@example.com'
     ), array(
        'title'  => 'extending iterators',
        'email'  => 'JaneDoe@example.com'
     )
));

The main idea is to influence how the Iterator returns the current element. Iterators are stackable, so you should use a RecursiveArrayIterator and wrap it into a RecursiveIteratorIterator. To achieve custom functionality, you can either subclass the RecursiveIteratorIterator (as shown below) or use additional iterators to decorate the RecursiveIteratorIterator:

class PostFormatter extends RecursiveIteratorIterator
{
    public function current()
    {
        $current = parent::current();
        switch($this->key()) {
            case 'email':
                $current = strtolower($current);
                break;
            case 'title':
                $current = ucwords($current);
                break;
            default:
                break;
        }
        return $current;
    }
}

Then you simply foreach over the iterator

$it = new PostFormatter(new RecursiveArrayIterator($data));
foreach($it as $key => $post) {
    echo "$key: $post", PHP_EOL;
}

and get

title: How To Work With Iterators
title: Introduction To Iterators
email: johndoe@example.com
title: Extending Iterators
email: janedoe@example.com

---

You can try to get the array back from the with iterator_to_array or iterator_apply functions. However, to get the values reapplied to the original array structure, you dont need an iterator:

array_walk_recursive($data, function(&$val, $key) {
    switch($key) {
        case 'title': $val = ucwords($val); break;
        case 'email': $val = strtolower($val); break;
        default: break;
    }
});
print_r($data);

Note: exchange Lambda with Function name when using PHP<5.3