Question

Possibly a dumb question, but I’m more used to Java and the likes and thus don’t get why I can do this:

class A:
    def __init__( self ):
        pass

a = A()
a.description = "whyyy"

print a.description

And have it print out whyyy instead of giving me an error.

Answer 1

Variables spring into existence by being assigned a value, and they
are automatically destroyed when they go out of scope.

For objects, you can add new fields dynamically on runtime. Note that this won’t change the class description. Only the current instance.

class A:
    def __init__( self ):
        pass

a = A()
a.description = "whyyy"

print a.description

b = A()

print b.description # Should return an error