Box\Spout\Reader\XLSX\SheetIterator::next PHP Метод

    public function next()
    {
        // Using isset here because it is way faster than array_key_exists...
        if (isset($this->sheets[$this->currentSheetIndex])) {
            $currentSheet = $this->sheets[$this->currentSheetIndex];
            $currentSheet->getRowIterator()->end();
            $this->currentSheetIndex++;
        }
    }