Something

foreach(array_keys($array) as $key0) {	//Main cat stuff	if(($newKey = str_replace(' ', '_', $key0)) != $key0) {		$array[$newKey] = $array[$key0];		unset($array[$key0]);		$key0 = $newKey;	}	foreach(array_keys($array[$key0]) as $key1) {		//sub cat stuff		if(($newKey = str_replace(' ', '_', $key1)) != $key1) {			$array[$key0][$newKey] = $array[$key0][$key1];			unset($array[$key0][$key1]);		}	}}