python class attribute

Question

i have a question about class attribute in python.

class base :
    def __init__ (self):
        pass
    derived_val = 1

t1 = base()
t2 = base ()

t2.deriv         


        

Answer 1

Another way (perhaps a more concise one) to demonstrate this:

class A():
   a1 = []
x = A()
y = A()
x.a1.append("test")
x.a1, y.a1
(['test'], ['test'])

class B():
   b1 = None
   def __init__(self):
      self.b1 = list()
r = B()
s = B()
r.b1.append("test")
r.b1, s.b1
(["test"], [])