python-面向对象:类与类之间的关系和特殊成员

# class Base:
#     def chi(self):
#         print("我会吃")
#
#
# # 派生类  => 子类
# class Foo(Base): # 这个类继承了Base类. Foo类是对Base的一个扩展
#     def he(self):
#         print("我会喝")
#
# f = Foo()
# f.chi()
# f.he()
#
#
# class Cat:  # 父类 => 基类  => 超类
#     def catch_mouse(self):
#         print("猫可以抓老鼠")
#
# class BosiCat(Cat):  # 子类 => 派生类
#     pass


# class Foo:
#     pass
#
#
# print(hash(Foo)) # 可哈希
# print(hash(Foo()))

# 我们写好的类和创建的对象默认都是可哈希的


# 去掉可哈希
# class Foo:
#     __hash__ = None # 当前类的对象不可哈希


# print(hash(Foo)) # 可哈希
# print(hash(Foo())) # TypeError: unhashable type: ‘Foo‘
#

# class Foo:
#     def chi(self, food):
#         print("我爱吃鱼和", food)
#
# class Bar:
#     def chi(self, food):
#         print("我爱吃肉和", food)
#
# dic = {Foo: "鸡蛋", Bar: "香肠"}
#
# for k, v in dic.items():
#     k().chi(v)

# 类名  => 变量名 -> 为了今天作业

# def func():
#     pass
#
# an = func
#
# an()



# class Base:
#     def __init__(self, num):
#         self.num = num
#     def func1(self):
#         print(self.num)
# class Foo(Base):
#     pass
# obj = Foo(123)
# obj.func1()



# class Base:
#     def __init__(self, num):
#         self.num = num
#     def func1(self):
#         print(self.num)
#
# class Foo(Base):
#     def func1(self):
#         print("Foo. func1", self.num)
#
# obj = Foo(123)
# obj.func1()


# class Base:
#     def __init__(self, num):
#         self.num = num
#     def func1(self):
#         print(self.num)
#         self.func2()
#     def func2(self):
#         print("Base.func2")
#
# class Foo(Base):
#     def func2(self):
#         print("Foo.func2")
# obj = Foo(123)
# obj.func1()



# class Base:
#     def __init__(self, num):
#         self.num = num
#
#     def func1(self):
#         print(self.num)
#         self.func2()
#
#     def func2(self):
#         print(111, self.num)
#
# class Foo(Base):
#      def func2(self):
#         print(222, self.num)
#
# lst = [Base(1), Base(2), Foo(3)]
# for obj in lst:
#  obj.func2()



# class Base:
#     def __init__(self, num):
#         self.num = num
#     def func1(self):
#         print(self.num)
#         self.func2()
#     def func2(self):
#         print(111, self.num)
#
# class Foo(Base):
#     def func2(self):
#         print(222, self.num)
#
# lst = [Base(1), Base(2), Foo(3)]
# for obj in lst:
#     obj.func1()

#
# class Foo:
#     def __init__(self): # 初始化操作
#         print("我是init,  我是老二")
#         print("初始化操作. 在创建对象的时候自动调用这个方法")
#
#     def __new__(cls, *args, **kwargs): # 创建, 它是真正的构造方法,  可以开辟内存
#         print("我是new. 我是老大")
#         return object.__new__(cls)
#
#
#     # 为了 对象()
#     def __call__(self, *args, **kwargs):
#         print("我是对象()")
#
#     # 对象[]
#     def __getitem__(self, item):
#         print("item=",item)
#         print("你执行了__getitem__")
#         return "哈哈"
#
#     # 对象[key] = value
#     def __setitem__(self, key, value):
#         print("key, ", key)
#         print("value, ", value)
#
#     # del lst[1]
#     def __delitem__(self, key):
#         print("key=", key)
#
#     # with 对象:
#     def __enter__(self):
#         print("我是enter")
#
#     # with 对象: 代码执行完毕. 最后执行这里
#     def __exit__(self, exc_type, exc_val, exc_tb):
#         print("我叫exit")
#
#     def __len__(self):
#         print("我的天哪")
#         return 3
#
#
# f = Foo()    # 自动执行__init__()
# f() # 调用-> __call__()
# print(callable(f)) # 对象()

# print(f["李嘉诚"]) # 自动调用__getitem__()
# f[‘jay‘] = "林俊杰"

# del f[‘哈哈‘]

# with f:
#     print("我是哈哈哈哈")

# with open() :


# lst = ["孙艺珍", "李金珠", "井柏然"]
#
# lst[2] # =>自动的调用__getitem__()


# def func():
#     pass
# func = 3
# print(callable(func)) # 判断xxx是否是可调用的

#
# f.__init__()  # 第一次这么写. 以后别这么写
# lst = [1,2,3,4]
# it = iter(lst)
#
# print(it.__next__())
#
# print(next(it)) # __next__()

# 面试之前翻一番
# 写出15个特殊成员, 并给出具体作用

# class H:
#     country = "大清"
#
# print(H.country)

# 面向对象编程的执行流程 ->
# 1. 加载类 -> 给类创建一个名称空间 -> 主要存放类变量.
# 2. 创建对象 -> 先找类. -> 根据类来开辟内存 -> 执行类中的__new__()  -> 执行__init__()  -> 返回对象



class Student:
    def __init__(self, name, no, gender, cls, age):
        self.name = name
        self.no = no
        self.gender = gender
        self.cls = cls
        self.age = age


    # 这个对象字符串的表示.
    def __str__(self): # 返回该对象的字符串表示形式
        return f"{self.name}, {self.no}, {self.gender}"

    def __repr__(self): # 该对象的官方的字符串表示形式
        return f"{self.name}, {self.no}, {self.gender}"


s = Student("董仲浩", "3", "男", "S18", "31")
print(s)