Python 3 OOP 将方法重定向到属性的方法

Question

Let suppose I have a class called A with an attribute b (class or object attribute, it doesn't matter) from a class B .

There is a B method called method_B

If I create an object a from class A , and I call a.method_b() from a , I want to be redirected to abmethod_b()

The corresponding code:

class A():

  def __init__(self):
    self.b = B()

class B():

  def __init__(self):
    self.val = 'a string'

  def method_B(self):
    # do something with self.val for example

# MAIN

a = A()

# this:
a.method_B()

# should be the same as:
a.b.method_B()

In fact, I want to avoid rewritting the method_B in class A like this:

class A():

  ...

  def method_B():
    self.b.method_B()

I have looked up an use of property and with descriptor but I don't know how to adapt them (if I can adapt them of course)

Thank you in advance for your help

Answer 1

Actually, when you are trying to get method_B() by creating object of class A, this will cause error since method_B() is not present in the class A. Your question is that you don't want to rewrite method_B() in class A, so you can use inheritance then you can get the same result from these below mentioned line of code.

this:

a.method_B()

will be same as if you will follow below code by using inheritance:

abmethod_B()

 class B(): def __init__(self): self.val = 'a string' def method_B(self): print("method B") class A(B): def __init__(self): self.b = B() # MAIN a = A() b = B() # this: a.method_B() # should be the same as: abmethod_B()