Problem regarding inheritance in python classes-CodePudding

I am trying to inherit methods from one a base class to another class, specifically the __str__ method, where I only need to change it a little by adding a note. Something like this.

class Person:
    def __init__(self, name=None):
        self.name = name

    def __str__(self):
        return ' Name: '   str(self.name)

And my second class.

class AnnotatedPerson(Person):
   def __init__(self, name=None, note=None):
       super().__init__(name=None)
       self.note = note

   def __str__(self):
       return ' Name: '   str(self.name)   'Note:'   str(self.note)

However this is not working, when printing print(AnnotatedPerson.__str__()) on an object I only get the part note and the name part in the __str__ method is set to None for objects that do have a value.

What is my mistake?

CodePudding user response：

This is the problem:

class AnnotatedPerson(Person):
   def __init__(self, name=None, note=None):
      super().__init__(name=None)

You are passing None as the value of the name argument, instead of passing through the argument you got. You just need:

      super().__init__(name)

This is an important point. When you say

     ...(name=name,...)

The first one is the name of an argument in the function being called. The second one is the name of a local variable in the function doing the calling. So:

     ...(name=None,...)

doesn't mention the local variable at all. It just forces a value into the function being called.

CodePudding user response：

You've been pass None to variables, soo you have no results from them, below the code i'm using using the string repr from Person.

class AnnotatedPerson(Person):
   def __init__(self, name=None, mother=None, father=None, born=None, died=None, note=None) -> None:
      super().__init__(name, mother, father, born, died)                # pass the arguments directly
      self.note=note

   def __str__(self) -> str:
       return f'{super().__str__()} Note: {self.note}'                # Here you have to pass only string representation from super().__str__() and add the note variable

if __name__ == "__main__":
    obj1 = AnnotatedPerson("Gerson", "Maria", "José", "19/12/1975","02/02/2022","Died like a wild horse")
    print(obj1)

#Name: Gerson Note: Died like a wild horse

Here a thread with a semelhant question:

python multiple inheritance passing arguments to constructors using super