Question

我想'标记'派生类的属性（在其他方面是相同的），以便父类的方法可以使用特定的属性。

在这个例子中，我正在构建神经元模型，每个神经元由“区域”组成，而“区域”又由“区段”组成。有一个neuron_region父类。 neuron_region父类有一个“连接”方法，它将一个段连接到另一个段（作为参数传递给它 - 在另一个神经元上）。需要有一种方法来标记派生类中的哪个段需要连接到。这样做的优雅方式是什么？

class neuron_region(object):
    def connect(external_segment)
       #connect segment 1 or segment 2 to external_segment, 
       #depending on which one is the right attribute

class child1(parent):
    #mark segment 1 as the segment to which to connect#
    self.seg1='segment 1'
    self.seg2='segment 2'

class child2(parent):
    self.seg1='segment 1'
    #mark segment 2 as the segment to which to connect#
    self.seg2='segment 2'

Answer 1

做最简单的事情可能会起作用 - 也许是这样的：

SEGMENTS = (SEGMENT_1, SEGMENT_2) = range(2)

class NeuronRegion(object):
    def __init__(self):
        self.connection = [None, None]
        self.chosen = 0
    def choose(self, segment):
        assert segment in SEGMENTS
        self.chosen = segment
    def connect(other_neuron_region):
       # remember to reset those to None when they're not needed anymore, 
       # to avoid cycles that prevent the garbage collector from doing his job:
       self.connection[self.chosen] = other_neuron_region
       other_neuron_region.connection[other_neuron_region.chosen] = self

class Child1(NeuronRegion):
   ''' other stuff '''

class Child2(NeuronRegion):
   ''' other stuff '''

<强> [编辑] 我不得不承认我不喜欢这个，但它确实按照你的要求行事，IMO。

Answer 2

你可以做到

class neuron_region(object):
    def connect(external_segment)
       #connect segment 1 or segment 2 to external_segment, 
       #depending on which one is the right attribute
    # the following can/must be omitted if we don't use the conn_attr approach
    @property
    def connected(self):
        return getattr(self, self.conn_attr)

class child1(parent):
    seg1 = 'segment 1'
    seg2 = 'segment 2'
    #mark segment 1 as the segment to which to connect#
    conn_attr = 'seg1'
    # or directly - won't work if seg1 is changed sometimes...
    connected = seg1


class child2(parent):
    seg1 = 'segment 1'
    seg2 = 'segment 2'
    #mark segment 2 as the segment to which to connect#
    conn_attr = 'seg2'
    # or directly - won't work if seg2 is changed sometimes...
    connected = seg2

在这里你甚至有两种方法：

子类定义conn_attr属性以确定哪个属性是用于连接的属性。它用在基类的connected属性中。如果是seg1。 seg2不时发生变化，这是可行的方法。
子类直接定义connected。因此，不需要重定向属性，但仅当所有使用的属性都没有更改时才有效。

在这两种方法中，父类只使用self.connected。

从父类调用任意子属性？

2 个答案: