Learn Python Identity Operators

Identity operators in Python are used to compare the memory location (identity) of objects, not just their values. They answer the question:

Do both variables refer to the same object in memory?

Python provides two identity operators:

is
is not

What Are Identity Operators?

Identity operators check whether two variables point to the same object.

Both may look similar, but they are very different checks.

Identity Operators Table

Operator	Description
`is`	Returns `True` if both variables refer to the same object
`is not`	Returns `True` if both variables refer to different objects

`is` vs `==` (Most Important Concept)

Operator	What it checks
`==`	Value equality
`is`	Memory identity

Example

Explanation:

== → values are equal
is → different objects in memory

Identity Operators with Immutable Types

Python may reuse memory for small immutable objects.

This happens due to interning.

Identity Operators with Mutable Types

Mutable objects usually do not share memory.

When Identity Becomes True for Mutable Objects

Both variables point to the same list.

Identity Operator with `None` (Best Practice)

The correct way to check for None is using is.

Why `is` Is Preferred for `None`

Using is avoids unexpected behavior.

Identity Operators with Functions

Both refer to the same function object.

Identity Operators with Boolean Values

Explanation:

True == 1 → True
True is 1 → False

Identity Operators with Integers (Tricky)

Small integers may be cached; larger ones usually are not.

Common Mistakes

Mistake 1: Using `is` for value comparison

Unreliable ❌

Correct:

Mistake 2: Using `==` to check `None`