How to read empty cells in PHPExcel without skippi

I need your help to solve one problem.

I tried to find answer, but I found none. I'm using PHPExcel 1.8.0 to read data from excel-file. And I'm using ReadFilter to read specific columns.

Main PHP Code.

        $price = UPLOAD_DIR . $price;

        $file_type = PHPExcel_IOFactory::identify($price);

        $filter = new ShipperReadFilter();

        $filter->getShipperSettings($shipper);          

        $reader = PHPExcel_IOFactory::createReader($file_type)->setReadDataOnly(true)->setReadFilter($filter)->load($price);

        $worksheet = $reader->getActiveSheet();

        $col_number = PHPExcel_Cell::columnIndexFromString($worksheet->getHighestDataColumn());

        $data = array();

        foreach ($worksheet->getRowIterator($filter->getStartRow()) as $row) {

            $cellIterator = $row->getCellIterator();

            $item = array();

            foreach ($cellIterator as $cell) {
                // May be PROBLEM is Here?
                array_push($item, $cell->getCalculatedValue());
            }

            array_push($data, $item);
        }           

        var_dump($data);

ReadFilter code.

class ShipperReadFilter implements PHPExcel_Reader_IReadFilter {

public $valid_columns = array();

public $start_row;

public function setValidColumns ($columns) {
    $this->valid_columns = $columns;
}

public function getShipperSettings ($shipper) {

    switch ($shipper) {

        // Shipper 1
        case 1 : 
            $this->setValidColumns(array('A', 'D', 'F'));
            $this->start_row = 4;
            break;

        // Shipper 2
        case 2 :
            $this->setValidColumns(array('A', 'R', 'T'));
            $this->start_row = 7;
            break;

        // Shipper 3
        case 3 :
            $this->setValidColumns(array('H', 'I', 'J'));
            $this->start_row = 14;
            break;
    }
}

public function getStartRow () {
    return $this->start_row;
}

public function readCell($column, $row, $worksheetName = '') {

    if (in_array($column, $this->valid_columns)) {
        return true;
    }
    return false;
}   
}

Result

array(3501) { 
   [0]=> array(2) { 
       [0]=> string(11) "01-00018239" 
       [1]=> float(2493) 
}

But I need this

array(3501) { 
[0]=> array(3) { 
    [0]=> string(11) "01-00018239" 
    [1]=> float(2493) 
    [2]=> null // or '', or 0
}

Is there the right way to solve this? Thank you.

By default, the cell iterator will only iterate over cells that actually exist

$cellIterator = $row->getCellIterator();
$cellIterator->setIterateOnlyExistingCells(false);

$item = array();
foreach ($cellIterator as $cell) {
    array_push($item, $cell->getCalculatedValue());
}

However, if all you're doing is building an array of calculated values for each row, then you might find that using the worksheet's rangeToArray() method is more efficient.

EDIT

To get only cells matching your read filter column list:

foreach ($cellIterator as $cell) {
    $item[$cell->getColumn()] = $cell->getCalculatedValue();
}
$item = array_intersect_key($item, array_flip($filter->valid_columns));

foreach ($cellIterator as $cell) {
    if(in_array($cell->getColumn(), $filter->valid_columns)) {
        array_push($item, $cell->getCalculatedValue());
    }
}