6
我想在返回代理对象的类上创建某种类型的描述符。代理对象在索引时检索对象的成员并将索引应用于它们。然后它返回总和。Python中的自适应描述符
例如，
class NDArrayProxy:
def __array__(self, dtype=None):
retval = self[:]
if dtype is not None:
return retval.astype(dtype, copy=False)
return retval
class ArraySumProxy(NDArrayProxy):
def __init__(self, arrays):
self.arrays = arrays
@property
def shape(self):
return self.arrays[0].shape
def __getitem__(self, indices):
return np.sum([a[indices]
for a in self.arrays],
axis=0)
这个解决方案工作得很好，而我实际的数组作为成员变量：
class CompartmentCluster(Cluster):
"""
Base class for cluster that manages evidence.
"""
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.variable_evidence = ArraySumProxy([])
class BasicEvidenceTargetCluster(CompartmentCluster):
# This class variable creates a Python object named basic_in on the
# class, which implements the descriptor protocol.
def __init__(self,
*,
**kwargs):
super().__init__(**kwargs)
self.basic_in = np.zeros(self.size)
self.variable_evidence.arrays.append(self.basic_in)
class ExplanationTargetCluster(CompartmentCluster):
"""
These clusters accept explanation evidence.
"""
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.explanation_in = np.zeros(self.size)
self.variable_evidence.arrays.append(self.explanation_in)
class X(BasicEvidenceTargetCluster, ExplanationTargetCluster):
pass
现在我改变了我的阵列成Python描述符（cluster_signal实现了描述符协议返回一个numpy数组）：
class CompartmentCluster(Cluster):
"""
Base class for cluster that manages evidence.
"""
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.variable_evidence = ArraySumProxy([])
class BasicEvidenceTargetCluster(CompartmentCluster):
# This class variable creates a Python object named basic_in on the
# class, which implements the descriptor protocol.
basic_in = cluster_signal(text="Basic (in)",
color='bright orange')
def __init__(self,
*,
**kwargs):
super().__init__(**kwargs)
self.variable_evidence.arrays.append(self.basic_in)
class ExplanationTargetCluster(CompartmentCluster):
"""
These clusters accept explanation evidence.
"""
explanation_in = cluster_signal(text="Explanation (in)",
color='bright yellow')
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.variable_evidence.arrays.append(self.explanation_in)
class X(BasicEvidenceTargetCluster, ExplanationTargetCluster):
pass
这不起作用因为append语句会附加描述符调用的结果。我需要的是附加绑定方法或类似的代理。什么是修改我的解决方案最好的方法？简而言之：变量basic_in和explanation_in是numpy阵列。他们现在是描述符。我想开发一些ArraySumProxy版本的描述符，而不需要实际的数组。
我不完全理解你的问题。你能否展示你以前如何使用这些类，以及发生了什么变化，以及你希望在变化之后如何使用它们？ – BrenBarn
@brenbarn：总结。 –
我无法从你的问题中知道哪些代码总是在使用中，哪些代码是新的。 –