python nested classes

Question

First of all, here\'s my test code, I\'m using python 3.2.x:

class account:
    def __init__(self):
        pass

    class bank:
        def __init__(self):         


        

Answer 1

a.bank is the class (not instance) since you've never created an instance of the bank on a. So if a.bank is a class, a.bank.balance is a method bound to that class.

This works however:

class account:
    def __init__(self):
        self.bank = account.bank()

    class bank:
        def __init__(self):
            self.balance = 100000

        def whitdraw(self, amount):
            self.balance -= amount

        def deposit(self, amount):
            self.balance += amount

a = account()
print a.bank.balance

Of course, as you show working code without nested classes, It really begs the question about why you want to use nested classes for this. I would argue that the non-nested version is much cleaner.