Imported class doesn't know local variables

Question

I have two files (Backupfile.py and Backupfile2.py).

Following is in Backupfile.py:

class Mater:
    def __init__(self):
        self.func()

    def func(self):
        from Backupfile2 import klasse

        newclass = klasse()

obj =[]
obj.append((1,1))
print(obj)

mater = Mater()

Now I want to import the class klasse from Backupfile2.py to Backupfile.py and add (2,2) to the list obj .

Following is in Backupfile2.py:

class klasse:
    def __init__(self):
        obj.append((2,2))
        print(obj)

However, why doesn't the class klasse know about the variable obj once it is imported?

Answer 1

The class klasse doesn't know about the variable obj because it is not in the same scope. Variables from the local scopes are not shared with variables from a class. One easy solution is to use the global keyword but I wouldn't use it. I would consider passing the obj reference in the method args, like this:

class Mater:
    def __init__(self, obj):
        self.obj = obj
        self.func()

    def func(self):
        from Backupfile2 import klasse

        newclass = klasse(self.obj)

obj =[]
obj.append((1,1))
print(obj)

mater = Mater(obj)

class klasse:
    def __init__(self, obj):
        obj.append((2,2))
        print(obj)

Apart from this specific question, I would advise you to take a beginner's course on Python.

Answer 2

I'm not sure about the answer because i'm not an expert and because i don't understand what do you want to do, but i think you miss the declaration of obj in the class "klasse", i think it should be something like

class klasse:
def __init__(self):
    self.obj = []
    self.obj.append((2,2))
    print(obj)

or if you want to use the obj declaration that you did out, your code should be something like

class Mater:
def __init__(self, obj):
    self.func(obj)

def func(self, obj):
    from Backupfile2 import klasse

    newclass = klasse(obj)

obj =[]
obj.append((1,1))
print(obj)

mater = Mater(obj)

and then your class "klasse" should be

class klasse:
def __init__(self, obj):
    obj.append((2,2))
    print(obj)

I hope it will help.