PHPOffice / PhpSpreadsheet

     *

     * @return float

     */

    public static function COUPDAYBS($settlement, $maturity, $frequency, $basis = 0)

    {

        $settlement = Functions::flattenSingleValue($settlement);

        $maturity = Functions::flattenSingleValue($maturity);

        $frequency = (int) Functions::flattenSingleValue($frequency);

        $basis = ($basis === null) ? 0 : (int) Functions::flattenSingleValue($basis);

        if (is_string($settlement = DateTime::getDateValue($settlement))) {

            return Functions::VALUE();

        }

        if (is_string($maturity = DateTime::getDateValue($maturity))) {

            return Functions::VALUE();

        }

        if (($settlement > $maturity) ||

            (!self::isValidFrequency($frequency)) ||

            (($basis < 0) || ($basis > 4))) {

            return Functions::NAN();

        }

        $daysPerYear = self::daysPerYear(DateTime::YEAR($settlement), $basis);

        $prev = self::couponFirstPeriodDate($settlement, $maturity, $frequency, false);

        return DateTime::YEARFRAC($prev, $settlement, $basis) * $daysPerYear;

    }

    /**

     * COUPDAYS.

     *

     * @return float

     */

    public static function COUPDAYSNC($settlement, $maturity, $frequency, $basis = 0)

    {

        $settlement = Functions::flattenSingleValue($settlement);

        $maturity = Functions::flattenSingleValue($maturity);

        $frequency = (int) Functions::flattenSingleValue($frequency);

        $basis = ($basis === null) ? 0 : (int) Functions::flattenSingleValue($basis);

        if (is_string($settlement = DateTime::getDateValue($settlement))) {

            return Functions::VALUE();

        }

        if (is_string($maturity = DateTime::getDateValue($maturity))) {

            return Functions::VALUE();

        }

        if (($settlement > $maturity) ||

            (!self::isValidFrequency($frequency)) ||

            (($basis < 0) || ($basis > 4))) {

            return Functions::NAN();

        }

        $daysPerYear = self::daysPerYear(DateTime::YEAR($settlement), $basis);

        $next = self::couponFirstPeriodDate($settlement, $maturity, $frequency, true);

        return DateTime::YEARFRAC($settlement, $next, $basis) * $daysPerYear;

    }

    /**

     * COUPNCD.