Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Parser.php
private function convertRef2d($cell)
    {
        // Convert the cell reference
        $cell_array = $this->cellToPackedRowcol($cell);
        list($row, $col) = $cell_array;

        // The ptg value depends on the class of the ptg.
        $ptgRef = pack('C', $this->ptg['ptgRefA']);

        return $ptgRef . $row . $col;
    }
private function convertRef2d($cell)
    {
        // Convert the cell reference
        $cell_array = $this->cellToPackedRowcol($cell);
        list($row, $col) = $cell_array;

        // The ptg value depends on the class of the ptg.
        $ptgRef = pack('C', $this->ptg['ptgRefA']);

        return $ptgRef . $row . $col;
    }
Convert an Excel reference such as A1, $B2, C$3 or $D$4 to a ptgRefV.

@param string $cell An Excel cell reference

@return string The cell in packed() format with the corresponding ptg