第二十天- 多继承 经典MRO 新式MRO super()

 1 # 画图排顺序 现用python版本已无法验证
 2 class A:
 3  pass
 4 class B(A):
 5  pass
 6 class C(A):
 7  pass
 8 class D(B, C):
 9  pass
10 class E:
11  pass
12 class F(D, E):
13  pass
14 class G(F, D):
15  pass
16 class H:
17  pass
18 class Foo(H, G):
19  pass
20 
21 #  结果 ： FOO--H--G--F--D--B--A--C--E

 1 class A:
 2     pass
 3 class B(A):
 4     pass
 5 class C(A):
 6     pass
 7 class D(B, C):
 8     pass
 9 class E(C, A):
10     pass
11 class F(D, E):
12     pass
13 class M(F, E):
14     pass
15 class N:
16     pass
17 class P(M,N):
18     pass
19 class G(P):
20     pass
21 class O:
22     pass
23 class X(O):
24     pass
25 class H(G, X, F):
26     pass
27 print(H.__mro__)
28 
29 
30 '''
31 # 拆 注意别漏了末尾的 “GXF”
32 # 当类里面只有单个继承时不需要 
33 L(H) = H + L(G) + L(X) + L(F) + GXF     HGPMXFDBECANO
34 
35 L(G) = G + L(P)               GPMFDBECAN
36 L(X) = X + L(O)               XO
37 L(F) = F + L(D) + L(E) + DE   FDBECA
38 
39 L(P) = P + L(M) + L(N) + MN   PMFDBECAN
40 L(O) = O
41 L(D) = D + L(B) + L(C) + BC    DBCA
42 L(E) = E + L(C) + L(A) + CA    ECA
43 
44 L(M) = M + L(F) + L(E) + FE    MFDBECA
45 
46 L(N) = N         
47 L(B) = B + L(A)  BA
48 L(C) = C + L(A)  CA
49 L(A) = A         
50 
51 
52 #  HGPMXFDBECANO

 1 # 当?类?法想调??类(MRO)?法
 2 class ShengWu:
 3     def dong(self): # 实例方法
 4         print(self)
 5         print("我是生物")
 6 
 7 class Animal(ShengWu):
 8    pass
 9 
10 class Cat(Animal):
11     def dong(self): # 子类中出现了和父类重名的内容. 表示对父类的方法的覆盖(重写).
12         super(Animal, self).dong() # 定位到Animal. 找Animal的下一个
13         # super(类, 对象).方法()  找MRO中的类. 找这个类的下一个. 去执行方法
14         print("我的猫也会动")
15 
16 # self 依然是谁调用就是谁
17 # 找MRO中的下一个
18 # Cat -> Animal -> ShengWu ->Object
19 
20 c = Cat()
21 print(c)
22 c.dong()