/**
* Recursively remove empty values from an array
*/
public static function array_filter_recursive($haystack)
{
foreach ($haystack as $key => $value) {
if (is_array($value)) {
$haystack[$key] = ZuhaSet::array_filter_recursive($haystack[$key]);
}
if (empty($haystack[$key])) {
unset($haystack[$key]);
}
}
return is_numeric(key($haystack)) ? array_values($haystack) : $haystack;
// reindex if keys are sequential instead of associative
}
