子類屬性不同的名稱

Question

我想要一個子類的屬性具有不同於它的父類的相同屬性的名稱，即使它意味着同樣的事情。例如，父類是具有屬性「高度」的Shape和具有類似屬性「直徑」的子類Circle。下面簡單介紹一下我現在擁有的內容，但我希望Circle類使用「直徑」而不是「高度」。處理這個問題的最好方法是什麼？

注意：我將從Circle繼承另一個類，該類還需要使用「直徑」而不是「高度」。謝謝！

class Shape(): 
    def __init__(self, shape, bar_args, height): 
     self.shape = shape 
     self.height = height 
     etc. 

class Circle(Shape): 
    def __init__(self, height, foo_args, shape='circle'): 
    Shape.__init__(self, shape, height) 
     self.height = height 
     etc. 

Answer 1

你可以定義一個property它訪問的讀寫訪問原始屬性：

class Circle(Shape): 
    def __init__(self, height, foo_args, shape='circle'): 
     Shape.__init__(self, shape, height) # assigns the attributes there 
     # other assignments 
    @property 
    def diameter(self): 
     """The diameter property maps everything to the height attribute.""" 
     return self.height 
    @diameter.setter 
    def diameter(self, new_value): 
     self.height = new_value 
    # deleter is not needed, as we don't want to delete this. 

如果你想這種行爲非常頻繁，你找物業與二傳手處理和getter太不方便，你可以去邁高和build自己descriptor class：

class AttrMap(object): 
    def __init__(self, name): 
     self.name = name 
    def __get__(self, obj, typ): 
     # Read access to obj's attribute. 
     if obj is None: 
      # access to class -> return descriptor object. 
      return self 
     return getattr(obj, self.name) 
    def __set__(self, obj, value): 
     return setattr(obj, self.name, value) 
    def __delete__(self, obj): 
     return delattr(obj, self.name) 

有了這個，你可以再做

class Circle(Shape): 
    diameter = AttrMap('height') 
    def __init__(self, height, foo_args, shape='circle'): 
     Shape.__init__(self, shape, height) # assigns the attributes there 
     # other assignments 

和diameter描述將重定向所有訪問它命名的屬性（這裏：height）。