Identity operators are used to compare the identity of objects.

They check whether two variables refer to the same object or different objects in memory.

Identity operators do not compare the values stored inside the objects.

Operator	Meaning
is	Returns True if both variables refer to the same object.
is not	Returns True if both variables refer to different objects.

Identity operators compare the memory location (object identity), not the value stored inside the object.

== Operator	is Operator
Compares values.	Compares object identity.
Checks content equality.	Checks memory reference.

Both variables contain the same value.

Therefore, a == b returns True.

Both variables refer to the same object in memory.

Therefore, a is b returns True.

Python provides the id() function to check the identity (memory reference) of an object.

If both IDs are the same, both variables refer to the same object.

a == b returns True because both lists contain the same values.

a is b returns False because they are different objects.

The IDs are different, so both variables refer to different objects.

Python may reuse immutable objects such as strings to improve memory usage.

Python may store both variables in the same memory location because strings are immutable.

If two variables refer to the same mutable object, the identity operator returns True.

Both variables refer to the same list object.

Both variables refer to the same list object.

When one variable modifies the list, the change is visible through the other variable.

The is not operator checks whether two variables refer to different objects.

Expression	Meaning	Result
a == b	Values are equal.	True
a is b	Same object.	False

Identity operators are useful for:

• Comparing object references.
• Checking None values.
• Validating memory references.

The recommended way to check whether a variable contains None is by using the is operator.

None is a singleton object in Python.

Using is None is the recommended and preferred style.

• is compares object identity.
• == compares values.
• id() returns the identity (memory reference) of an object.
• Mutable objects usually have different identities even if their values are equal.
• Immutable objects may share the same memory location.

Operator	Purpose
is	Checks whether two variables refer to the same object.
is not	Checks whether two variables refer to different objects.
==	Checks whether two values are equal.