[phpexcel] PHPExcel - set cell type before writing a value in it

For Numbers with leading zeroes and comma separated:

You can put 'A' to affect the entire column'.

$objPHPExcel->getActiveSheet()->getStyle('A1')->getNumberFormat()->setFormatCode(PHPExcel_Style_NumberFormat::FORMAT_NUMBER_COMMA_SEPARATED1);

Then you can write to the cell as you normally would.