钻石继承

钻石继承

新式类：广度优先

经典类：深度优先

钻石问题：D->B->C->A

class A(object):
    def test(self):
        print('A')

class B(A):
    def test(self):
        print('B')

class C(A):
    def test(self):
        print('C')

class D(B,C):
    #def test(self):
    #    print('D')
    pass

print(D.__mro__) #只有新式才有这个属性可以查看线性列表，经典类没有这个属性
#(<class '__main__.D'>, <class '__main__.B'>, <class '__main__.C'>, <class '__main__.A'>

小乌龟问题：F->D->B->E->C->A

class A(object):
    def test(self):
        print('from A')

class B(A):
    def test(self):
        print('from B')

class C(A):
    def test(self):
        print('from C')

class D(B):
    def test(self):
        print('from D')

class E(C):
    def test(self):
        print('from E')

class F(D,E):
    # def test(self):
    #     print('from F')
    pass
f1=F()
f1.test()
print(F.__mro__) 
#(<class '__main__.F'>, <class '__main__.D'>, <class '__main__.B'>, <class '__main__.E'>, <class '__main__.C'>, <class '__main__.A'>, <class 'object'>)