public String closestWeekday(String field)
    {
        String newField = "";

        for(int i = 1; i <= field.length(); i++)
            {
                if(isNumber(field.substring(i - 1, i)))
                {
                    newField = newField + field.substring(i - 1, i);
                }
                else if(field.substring(i - 1, i).equals(" "))
                {
                    //  leave
                }
                else
                {
                    newField = "~invalid~";
                    break;
                }
        }
        return newField;
    }