Tools::prepareKeys

static function prepareKeys(array $fields, array $keyList, $checkNull = false)
{
	$result = array(
		'EXIST' => array(),
		'MISSING' => array()
	);
	if (empty($keyList))
		return false;

	if (empty($fields))
	{
		$result['MISSING'] = $keyList;
		return $result;
	}

	$checkNull = ($checkNull === true);
	if (!$checkNull)
		$fields = array_filter($fields, 'BitrixCatalogHelpersTools::clearNullFields');

	foreach ($keyList as &$key)
	{
		if (!array_key_exists($key, $fields))
			$result['MISSING'][] = $key;
		else
			$result['EXIST'][] = $key;
	}
	unset($key);
	return $result;
}