Variables in python

Question

class Myclass:
def __init__(self,n=1):

self.__n=n

def val_n(self):
return (self.__n)

obj=Myclass(2)
obj.__n=3
print(obj.val_n())

What is the output? I'm confused between 2 and 3.

Answer 1

2.

The syntax with two underscores within the class definition leads to name-mangling:

The attribute __n will actually be named _Myclass__n and can be accessed as such.

obj.__n = 3 writes into an instance dynamically, outside of the class definition, so it will create a new attribute that is named __n.

The other attribute is still there, though, and val_n, being defined within the class, accesses that one.

Answer 2

+