Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Shared/Date.php
public static function dayStringToNumber($day)
    {
        $strippedDayValue = (str_replace(self::$numberSuffixes, '', $day));
        if (is_numeric($strippedDayValue)) {
            return (int) $strippedDayValue;
        }

        return $day;
    }
public static function dayStringToNumber($day)
    {
        $strippedDayValue = (str_replace(self::$numberSuffixes, '', $day));
        if (is_numeric($strippedDayValue)) {
            return (int) $strippedDayValue;
        }

        return $day;
    }
Strips an ordinal froma numeric value.

@param string $day Day number with an ordinal

@return int|string The integer value with any ordinal stripped, or the original string argument if it isn't a valid numeric