Class attributes vs instance attributes

  • dictionary
  • mutable
  • list
  • class

Class attributes are shared across all instances of a class. This can be advantageous when used correctly but often will trip up new users.

class A(object):
    data = []


a1 = A()
a1.data.append(1)

a2 = A()
print(a2.data)
# [1]