/**
* How many columns add/remove to coordinate
* @param int $numCols positive value will add, negative will remove
* @return Coordinate
* @throws PhpExcelException
*/
public function shiftColBy($numCols = 0)
{
if (!is_int($numCols)) {
throw new PhpExcelException('Only integer values are allowed.');
}
$colNum = ExcelHelper::getExcelColumnNumber($this->col) + $numCols;
if ($colNum < 1) {
throw new PhpExcelException('Number of rows would get below 1.');
}
$this->col = ExcelHelper::getExcelColumnName($colNum);
return $this;
}
