flattenArray.php

<?php

/**
 * Flatten an array, preserving keys.
 *
 * @author Craig Anderson <craiga@craiga.id.au>
 * @link https://gist.github.com/craiga/5855194
 */
function flattenArray($in) {
  	$out = array();
	foreach($in as $key => $value) {
		if(is_array($value)) {
			$out = array_merge($out, flattenArray($value));
		}
		else {
			$out[$key] = $value;
		}
	}
	return $out;
}