- var_dump: documentation ( source)
- iterator_to_array: documentation ( source)
<?php
$results = [];
$results[] = ['topic' => 'Command Line'];
$results[] = ['topic' => 'Symfony General'];
$results[] = ['topic' => 'Dependency Injection'];
$results[] = ['topic' => 'Validation'];
$results[] = ['topic' => 'Cache'];
$results[] = ['topic' => 'Form'];
$results[] = ['topic' => 'Doctrine'];
var_dump($results);
var_dump(iterator_to_array(new \RecursiveIteratorIterator(new \RecursiveArrayIterator($results)), false));