Python 3:如何为派生类编写一个\uu iter\uuuuu方法,以便它扩展基类“\uu iter\uuuuu方法”的行为

这行不通,因为 super().__iter__() 是生成器,在此上下文中调用生成器没有意义。您要做的是迭代该生成器返回的内容,并从 __iter__ 在里面 Data :

Python 2:

def __iter__(self):
    for i in super().__iter__():
        yield i
    yield 'd', self.D

但在Python 3中,可以更简洁地编写为:

def __iter__(self):
    yield from super().__iter__()
    yield 'd', self.D

必须委托给基类:

In [1]: class Base:
   ...:     A = False
   ...:     B = ''
   ...:     C = ''
   ...:
   ...:     def __iter__(self):
   ...:         yield 'a', self.A
   ...:         yield 'b', self.B
   ...:         yield 'c', self.C
   ...:

In [2]: class Data(Base):
   ...:     D = ''
   ...:
   ...:     def __iter__(self):
   ...:         yield from super().__iter__()
   ...:         yield 'd', self.D
   ...:

In [3]: print(list(Data()))
[('a', False), ('b', ''), ('c', ''), ('d', '')]

In [4]: print(dict(Data()))
{'c': '', 'b': '', 'd': '', 'a': False}

Python 3允许 yield from 语法,在Python 2中使用:

class Base(object): # make sure to inherit from object for super to work
    A = False
    B = ''
    C = ''

    def __iter__(self):
        yield 'a', self.A
        yield 'b', self.B
        yield 'c', self.C

class Data(Base):
    D = ''

    def __iter__(self):
        for x in super(Data, self).__iter__():
            yield x
        yield 'd', self.D