多重继承,多继承
多重继承代码示例:
### ref https://zhuanlan.zhihu.com/p/97995434 class A: def func1(self): print("in A func1") def func2(self): print("in A func2") class B: def func2(self): print("in B func4") def func3(self): print("in B func3") class C(A, B): pass c = C() print(c.func1()) # in func1 print(c.func2()) # in func2 print(c.func3()) # in func3 # 原因解析: # 1.c 是类 C 的一个实例化对象,C 中没有任何内容 # 2.c.func1(),先从父类 A 中找,找不到再从父类 B 中找 # 3.同理,c.func3()、c.func2() 查找顺序一样 # 4.因为父类 A 中有 func2 方法,因此 c.func2() 执行的是父类 A 中的
结果
in A func1 None in A func2 None in B func3 None
代码示例:
### ref https://www.cnblogs.com/jiangzuofenghua/p/11413777.html class Printable: def _print(self): print(111,self.content) class Document: #第三方库,不允许修改 def __init__(self,content): self.content = content class Word(Document): pass #第三方库,不允许修改 class PrintableWord(Printable,Word): pass print(222,PrintableWord.__dict__) print(333,PrintableWord.mro()) pw = PrintableWord('test string') pw._print()
print(dir(PrintableWord))
结果:
"D:\Program Files\python_3_6_4\python.exe" D:/untitled2/xdemo.py 222 {'__module__': '__main__', '__doc__': None} 333 [<class '__main__.PrintableWord'>, <class '__main__.Printable'>, <class '__main__.Word'>, <class '__main__.Document'>, <class 'object'>] 111 test string
代码示例:
#### ref https://blog.csdn.net/u013008795/article/details/90412084
def printable(cls): def _print(self): print(self.content,'装饰器') cls.print = _print return cls class Document: #第三方库,不允许修改 def __init__(self,content): self.content = content class Word(Document): pass #第三方库,不允许修改 @printable #先继承,后装饰 class PrintableWord(Word): pass print(PrintableWord.__dict__) print(PrintableWord.mro()) pw = PrintableWord('test string') pw.print()
print(dir(PrintableWord))