python - 如何使用动态名称实现 property()(在 python 中)

Question

我正在为单个神经元编写模拟程序。因此我必须处理很多参数。现在的想法是我有两个类，一个用于 SingleParameter 和一个参数集合。我使用 property() 来轻松访问参数值并使代码更具可读性。这非常适合单个参数，但我不知道如何为集合实现它，因为我想在 SingleParameter 之后命名集合中的属性。这里有一个例子:

class SingleParameter(object):
  def __init__(self, name, default_value=0, unit='not specified'):
    self.name = name
    self.default_value = default_value
    self.unit = unit
    self.set(default_value)
  def get(self):
    return self._v
  def set(self, value):
    self._v = value
  v = property(fget=get, fset=set, doc='value of parameter')

par1 = SingleParameter(name='par1', default_value=10, unit='mV')
par2 = SingleParameter(name='par2', default_value=20, unit='mA')

# par1 and par2 I can access perfectly via 'p1.v = ...'
# or get its value with 'p1.v'

class Collection(object):
  def __init__(self):
    self.dict = {}
  def __getitem__(self, name):
    return self.dict[name] # get the whole object
    # to get the value instead:
    # return self.dict[name].v
  def add(self, parameter):
    self.dict[parameter.name] = parameter
    # now comes the part that I don't know how to implement with property():
    # It shoule be something like
    # self.__dict__[parameter.name] = property(...) ?

col = Collection()
col.add(par1)
col.add(par2)
col['par1'] # gives the whole object

# Now here is what I would like to get:
# col.par1 -> should result like col['par1'].v
# col.par1 = 5 -> should result like col['par1'].v = 5

---

为了理解 property() 而提出的其他问题:

• Why do managed attributes just work for class attributes and not for instance attributes in python?
• How can I assign a new class attribute via __dict__ in python?

Answer 1

查看内置函数 getattr 和 setattr。你可能会更快乐。