We’ve learned so far that a class is a schematic for a data type and an object is an instance of a class, but why is there such a strong need to differentiate the two if each object can only have the methods and class variables the class has? This is because each instance of a class can hold different kinds of data.

The data held by an object is referred to as an instance variable. Instance variables aren’t shared by all instances of a class — they are variables that are specific to the object they are attached to.

Let’s say that we have the following class definition:

class FakeDict:
  pass

We can instantiate two different objects from this class, fake_dict1 and fake_dict2, and assign instance variables to these objects using the same attribute notation that was used for accessing class variables.

fake_dict1 = FakeDict()
fake_dict2 = FakeDict()

fake_dict1.fake_key = "This works!"
fake_dict2.fake_key = "This too!"

# Let's join the two strings together!
working_string = "{} {}".format(fake_dict1.fake_key, fake_dict2.fake_key)
print(working_string)
# prints "This works! This too!"