具有多个基类的类中的继承属性问题

Question

EDIT: Thanks for the information about the class attributes. I understand these are similar to static in other OO languages. Now in the following code, I wish to use the __init__ of the base classes to set x and y in the derived class. Any guidance would be appreciated.

class Base1:
  def __init__(self, x):
      self.x = x

class Base2:
  def __init__(self, y):
      self.y = y

class Derv (Base1, Base2):
  def __init__(self, x, y):
      self.x = x
      self.y = y

OLD:

Related to Multiple inheritance: The derived class gets attributes from one base class only?

Now, what is happening in the following example (dictionary of d is empty):

class Base1:
  x = 10

class Base2:
  y = 10

class Derv (Base1, Base2):
  pass


d=Derv()
print (d.__dict__)

Although this works when we change the code to following:

class Base1:
  x = 0
  def __init__(self, x):
      self.x = x

class Base2:
  y = 0
  def __init__(self, y):
      self.y = y

class Derv (Base1, Base2):
  def __init__(self, x, y):
      self.x = x
      self.y = y

I think this is more because of defining x and y in the __init__ method of Derv . But, if I wish to set the values using base class constructors, what is the correct way?

Answer 1

Easiest and best: just call the initializers in each base!

class Derv(Base1, Base2):
    def __init__(self, x, y):
        Base1.__init__(self, x)
        Base2.__init__(self, y)