python note 23 组合

浅浅的花香味﹌ 2021-11-11 14:34 183阅读 0赞

1、主动调用其他类的成员

方式一

class Base(object):
        def f1(self):
            print('5个功能')
    
    
    class Foo(object):
        def f1(self):
            print('3个功能')
            Base.f1(self)
    
    
    obj = Foo()
    obj.f1()
    
    总结:
    Base.实例方法(自己传self)
    与继承无关

方式二

# ########### 方式二:按照类的继承顺序,找下一个.
    class Foo(object):
        def f1(self):
            super().f1()
            print('3个功能')
    
    class Bar(object):
        def f1(self):
            print('6个功能')
    
    
    class Info(Foo, Bar):
        pass
    
    # obj = Foo()
    # obj.f1()
    
    obj = Info()
    obj.f1()

2、特殊成员

class Foo(object):
    
        def __init__(self,a1,a2):
            self.a1 = a1
            self.a2 = a2
        
        def __call__(self, *args, **kwargs):
            print(11111,args,kwargs)
            return 123
    
        def __getitem__(self, item):
            print(item)
            return 8
    
        def __setitem__(self, key, value):
            print(key,value,111111111)
    
        def __delitem__(self, key):
            print(key)
    
        def __add__(self, other):
            return self.a1 + other.a2
    
        def __enter__(self):
            print('1111')
            return 999
    
        def __exit__(self, exc_type, exc_val, exc_tb):
            print('22222')
    
    # 1. 类名() 自动执行 __init__
    # obj = Foo(1,2)
    
    # 2. 对象() 自动执行 __call__
    # ret = obj(6,4,2,k1=456)
    
    # 3. 对象['xx']  自动执行 __getitem__
    # ret = obj['yu']
    # print(ret)
    
    # 4. 对象['xx'] = 11  自动执行 __setitem__
    # obj['k1'] = 123
    
    # 5. del 对象[xx]     自动执行 __delitem__
    # del obj['uuu']
    
    # 6. 对象+对象         自动执行 __add__
    # obj1 = Foo(1,2)
    # obj2 = Foo(88,99)
    # ret = obj2 + obj1
    # print(ret)
    
    # 7. with 对象        自动执行 __enter__ / __exit__
    # obj = Foo(1,2)
    # with obj as f:
    #     print(f)
    #     print('内部代码')
    
    # 8. 真正的构造方法
    # class Foo(object):
    #     def __init__(self, a1, a2):     # 初始化方法
    #         """
    #         为空对象进行数据初始化
    #         :param a1:
    #         :param a2:
    #         """
    #         self.a1 = a1
    #         self.a2 = a2
    #
    #     def __new__(cls, *args, **kwargs): # 构造方法
    #         """
    #         创建一个空对象
    #         :param args:
    #         :param kwargs:
    #         :return:
    #         """
    #         return object.__new__(cls) # Python内部创建一个当前类的对象(初创时内部是空的.).
    #
    # obj1 = Foo(1,2)
    # print(obj1)
    #
    # obj2 = Foo(11,12)
    # print(obj2)

转载于:https://www.cnblogs.com/P-Z-W/p/11029470.html