can Inner Class reference the Outer Class's static variable?

[raykuan]

In the nested class, can Inner Class reference the Outer Class's static variable?

class Outer(object):
    a = 111

    class Inner(object):

        b = Outer.a.   # NameError: name 'Outer' is not defined

        @staticmethod
        def get_a(cls):
            return Outer.a  # OK

[Larz60+]

why make your code complicated?

why not:

class Outer(object):
    def __init__(self):
        self.a = 111

print(f"Outer.a = {Outer().a}")

Output:
Outer.a = 111

[Gribouillis]

You can do this

class Outer(object):
    a = 111
 
    class Inner(object):

        @staticmethod
        def get_a(cls):
            return Outer.a  # OK

    Inner.b = a

[deanhystad]

Class variable, not static variable. This is Python, not C++.

The answer to your question is yes and no. You cannot use class variables in Outer when assigning class variables in Inner because class Outer does not exist yet when you create class variables for Inner. However, methods in Inner can see Outer just fine.

class Outer(object):
    a = 1
 
    class Inner(object):
        a = 2

        @classmethod
        def aay(cls):
            return cls.a, Outer.a

print(Outer.Inner.aay())

Output:
(2, 1)

This also works for instance methods of Inner.

[raykuan]

Find a way to handle it now, using inheritance

class _(object):
    a = 100

class Outer(_):

    class Inner(object):
        b = _.a   # OK
 
        @staticmethod
        def get_a(cls):
            return Outer.a  # OK

[deanhystad]

What are you trying to achieve? I was confused by your original post and more confused now. Why do you want a class variable in Inner that is initialized to the value of a class variable in Outer? I don't see how this makes any sense. Could you please describe the purpose for this?

[SharonDutton]

Unlike inner class, a static nested class cannot access the member variables of the outer class. It is because the static nested class doesn't require you to create an instance of the outer class. OuterClass. NestedClass obj new OuterClass.We can not have a « url snipped » static method in a nested inner class because an inner class is implicitly associated with an object of its outer class so it cannot define any static method for itself. For example, the following program doesn't compile.

Gribouillis write Jul-01-2022, 07:56 AM:
Offsite link promotion snipped. Pleas read What to NOT include in a post.