4.类定义实例：学校人事管理系统中的类

import datetime

# TypeError不同类型之间的无效操作
class PersonTypeError(TypeError):
    pass

class PersonValueError(TypeError):
    pass

# 公共人员类
class Person(object):
    _num = 0

    def __init__(self, name, sex, birthday, ident):
        if not (isinstance(name, str) and 
                sex in ('男', '女')):
            raise PersonValueError(name, sex)
        try:
            birth = datetime.date(*birthday)
        except:
            raise PersonValueError('Wrong data:', birthday)
        self._name = name
        self._sex = sex
        self._birthday = birthday
        self._id = ident
        Person._num += 1

    def id(self): return self._id   # 取得该人员记录中的人员编号
    def name(self): return self._name   # 取得该人员记录中的姓名
    def sex(self): return self._sex  # 取得该人员记录中的性别
    def birthday(self): return self._birthday   # 取得该人员记录中的出生年月日
    def age(self): return (datetime.date.today().year - 
                           self._birthday.year) # 取得该人员的年龄
    
    def set_name(self,name): # 修改人员名字
        if not isinstance(name,str):
            raise PersonValueError('set_name:',name)
        self.name = name

    def __lt__(self,another):   # 基于人员编号比较两个记录
        if not isinstance(another,Person):
            raise PersonTypeError(another)
        return self._id < another._id

    @classmethod
    def num(cls): return Person._num
    
    def __str__(self):
        return ' '.join((self._id, self._name,
                        self._sex, str(self._birthday)))
    
    def details(self):  # 给出人员记录里保存的数据详情
        return ', '.join(('编号: ' + self._id,
                          '姓名: ' + self._name,
                          '性别: ' + self._sex,
                          '出生日期: ' + str(self._birthday)))

# 学生类
class Student(Person):
    _id_num = 0

    @classmethod
    def _id_gen(cls):  # 实现学号生成规则
        cls._id_num += 1
        year = datetime.date.today().year
        return '1{:04}{:05}'.format(year, cls._id_num)
        
    def __init__(self, name, sex, birthday, department):
        Person.__init__(self, name, sex, birthday,
                        Student._id_gen())
        self._department = department
        self._enroll_data = datetime.date.today()
        self._courses = {}  # 一个空字典

    def department(self): return self._department   # 取得学生所属院系
    def en_year(self): return self._enroll_data # 取得学生的入学年度

    def set_course(self, course_name):  # 设置选课
        self._courses[course_name] = None

    def set_score(self, course_name, score):    # 设置课程成绩
        if course_name not in self._courses:    # 这里假设必须先选课，最后才能设定课程成绩
            raise PersonValueError('No this course selected:', course_name)
        self._courses[course_name] = score

    def scores(self): return [(cname, self._courses[cname])
                              for cname in self._courses] # 取得学生成绩单

    def details(self):
        return ", ".join((Person.details(self),
                          '入学日期：' + str(self._enroll_data),
                          '院系： ' + self._department,
                          '课程记录： ' + str(self.scores())))
    
# 教职工类
class Staff(Person):
    _id_num = 0

    @classmethod
    def _id_gen(cls, birthday):
        cls._id_num += 1
        birth_year = datetime.date(*birthday).year
        return '0{:04}{:05}'.format(birth_year, cls._id_num)

    def __init__(self, name, sex, birthday, entry_date=None):
        super().__init__(name, sex, birthday,
                         Staff._id_gen(birthday))
        if entry_date:
            try:
                self._entry_date = datetime.date(*entry_date)
            except:
                raise PersonValueError('Wrong date: ', entry_date)
        else:
            self._entry_date = datetime.date.today()
        
        self._salary = 1720  # 默认设为最低工资，可修改
        self._department = '未定'  # 需要另行设定
        self._position = '未定'  # 需要另行设定

    def salary(self): return self._salary  # 取得教职工的工资额
    def department(self): return self._department  # 取得教职工的职位
    def position(self): return self._position  # 取得教职工的所属院系

    def set_salary(self, amount):  # 设置教职工的工资额
        if not type(amount) is int:
            raise TypeError
        self._salary = amount

    def set_position(self, position):  # 设置教职工的职位
        self._position = position
    
    def set_department(self, department):  # 设置教职工的所属院系
        self._department = department

    def details(self):
        return ", ".join((super().details(),
                          '入职日期：' + str(self._entry_date),
                          '院系：' + self._department,
                          '职位：' + self._position,
                          '工资：' + str(self._salary)))

p1 = Staff('路飞', '男', (1998, 3, 7))
p2 = Staff('女帝', '女', (1998, 4, 21))
p3 = Student('香吉士', '男', (1998, 8, 17),'云计算系')

plist2 = [p1, p2, p3]

for p in plist2:
    print(p)

print('\nAfter sorting:')

p1.set_department('数学')
p1.set_position('副教授')
p1.set_salary(8400)

p3.set_course('python基础')
p3.set_score('python基础', 90)
p3.set_course('数据结构与算法')
p3.set_score('数据结构与算法', 99)


plist2.sort()
for p in plist2:
    print(p.details())

print('People created:', Person.num(), '\n')