Difference between == and is

• == (Equality)
• Take an example of identical twins. Look wise they are exactly same (equal).
• Expression evaluates to True if two objects (referred by variables) have the same contents (or are equal).

• is (Identity)
• Take an example of identical twins. Both are different human beings.
• Expression evaluates to True if two variables point to the same (identical) object.

>>> a = [1,2,3]
>>> id(a)
4557217944
>>> b = a
>>> id(b)
4557217944

>>> a == b
True
>>> a is b
True

Note: Here a is a list, which has a particular identity (4557217944), and we are assigning a to b, so b has the same identity as a (4557217944).

>>> a = [1,2,3]
>>> id(a)
4557293400
>>> b = [1,2,3]
>>> id(b)
4557140408

>>> a == b
True
>>> a is b
False

Note: Here a is a list, which has a particular identity (4557293400), and we are creating a new list b, so b has a different identity (4557140408) than a's identity (4557293400).