PyPyPath

Module 3: Operators in Python

Identity Operators

Identity operators check if two variables point to the same object in memory: is and is not. A common use is comparing a value to None.

About 6 minutes

== compares values. is checks if two names refer to the exact same thing (same identity).

Example code
a = [1, 2]
b = [1, 2]
c = a

print(a == b)   # True (same contents)
print(a is b)   # False (different lists)
print(a is c)   # True (same list object)

Use `value is None` to check for “no value” — common in data cleaning later.

Practice

Create x = None. Print x is None and x is not None.

Key takeaways

  • is / is not check same object, not just equal values.
  • Often used with None.
  • For equal values of numbers/strings, == is usually enough.

Quick check: Identity Operators

Question 1 of 2

When is `is` commonly used with None?