I have three classes as shown below:

class abc():
  def __init__(self):
    self.expiry_date = None
  def some_print():
     print(self.expiry_date)

class zxc(abc):
    def __init__(self, expiry_date):
        self.expiry_date = expiry_date
        abc.__init__()
    def some():
        self.some_print()

class xyz(abc):
    def __init__():
       abc.__init__()
    def cute():
      self.expiry_date = date.today()
      z = zxc(self.expiry_date)
      z.some()

What I am trying to do is pass the variable expiry_date from class xyz to the class zxc. Class xyz creates an instance of abc so the expiry_date variable defined in the constructor of the class abc gets updated. Since, I am creating a new object of class zxc which initializes abc this variable is None again.

Is there any way I can pass expiry_date from xyz to zxc while updating the constructor variable in abc?

So, when I call z.some() I want it to print today's date.

CodePudding user response：

Your problem is captured in these lines:

class A():
  def __init__(self):
    self.expiry_date = None

class B(abc):
    def __init__(self, expiry_date):
        self.expiry_date = expiry_date
        A.__init__()

First, when B gets instantiated it sets it's member field expiry_date to the value passed in. Then, it calls the super class __init__() (which, for the record, you can use super().__init__()). Then, in A, the member field for expiry_date is set to None. This is why it appears as though B is not setting that value - it is, but then it's being removed.