PHPOffice / PhpSpreadsheet

     *

     * @return int

     */

    public static function STRINGLENGTH($value = '')

    {

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

        if (is_bool($value)) {

            $value = ($value) ? \PhpOffice\PhpSpreadsheet\Calculation::getTRUE() : \PhpOffice\PhpSpreadsheet\Calculation::getFALSE();

        }

        return mb_strlen($value, 'UTF-8');

    }

    /**

     * LOWERCASE.

     *

     * @return string

     */

    public static function LOWERCASE($mixedCaseString)

    {

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

        if (is_bool($mixedCaseString)) {

            $mixedCaseString = ($mixedCaseString) ? \PhpOffice\PhpSpreadsheet\Calculation::getTRUE() : \PhpOffice\PhpSpreadsheet\Calculation::getFALSE();

        }

        return \PhpOffice\PhpSpreadsheet\Shared\StringHelper::strToLower($mixedCaseString);

    }

    /**

     * UPPERCASE.

     *

     * @return string

     */

    public static function UPPERCASE($mixedCaseString)

    {

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

        if (is_bool($mixedCaseString)) {

            $mixedCaseString = ($mixedCaseString) ? \PhpOffice\PhpSpreadsheet\Calculation::getTRUE() : \PhpOffice\PhpSpreadsheet\Calculation::getFALSE();

        }

        return \PhpOffice\PhpSpreadsheet\Shared\StringHelper::strToUpper($mixedCaseString);

    }

    /**

     * PROPERCASE.

     *

     * @return string

     */

    public static function PROPERCASE($mixedCaseString)

    {

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

        if (is_bool($mixedCaseString)) {

            $mixedCaseString = ($mixedCaseString) ? \PhpOffice\PhpSpreadsheet\Calculation::getTRUE() : \PhpOffice\PhpSpreadsheet\Calculation::getFALSE();

        }

        return \PhpOffice\PhpSpreadsheet\Shared\StringHelper::strToTitle($mixedCaseString);

    }

    /**

     * REPLACE.