src/Compo/ImportBundle/Exporter/Writer/XmlExcelWriter.php
public static function formatColumnName($number)
    {
        for ($char = ''; $number >= 0; $number = (int) ($number / 26) - 1) {
            $char = \chr($number % 26 + 0x41) . $char;
        }

        return $char;
    }
public static function formatColumnName($number)
    {
        for ($char = ''; $number >= 0; $number = (int) ($number / 26) - 1) {
            $char = \chr($number % 26 + 0x41) . $char;
        }

        return $char;
    }
public static function formatColumnName ( $ number ) { for ( $ char = '' ; $ number >= 0 ; $ number = ( int ) ( $ number / 26 ) - 1 ) { $ char = \ chr ( $ number % 26 + 0x41 ) . $ char ; } return $ char ; }
Returns letter for number based on Excel columns.

@param int $number

@return string
Returns letter for number based on Excel columns .