List of Identity Operators

Types of Identity Operators:

1. Identity Operator (is)

   is checks if two variables refer to the same object in memory.

   a = [1, 2]  
   b = a  
   print(a is b)  # True

   Output: True

   Explanation:

   Both a and b point to the same list in memory. Hence, a is b returns True.

2. Negative Identity Operator (is not):

   is not returns True if two variables do not refer to the same object.

   x = [10, 20]  
   y = [10, 20]  
   print(x is not y)   # True

   Output: True

   Explanation:

   Even though x and y have the same values, they are stored at different memory locations. So, x is not y returns True.

Why Use Identity Operators?

They are useful when we want to:

• Check if two variables refer to the same object (not just same value).
• Differentiate between is and == (value vs identity).
• Understand reference handling in Python objects.

Example:

a = [1, 2, 3]
b = a
c = [1, 2, 3]

print(a is b)       # True
print(a is c)       # False
print(a == c)       # True

Explanation:

• a is b → True because both refer to the same list in memory.
• a is c → False because c is a different list, even though the values are same.
• a == c → True because both have equal contents (value-wise).

Note: is compares identities (memory address), while == compares values.

Summary

• is: True if both refer to same object in memory
• is not: True if both refer to different objects
• ==: Compares values
• Identity ≠ Value