Understanding Objects in Python: Mutability vs Immutability Explained Simply

Python treats everything as an object, even the data types you work with daily. To write clean, bug-free code, it's crucial to understand how Python objects behave—especially when it comes to mutability and immutability.

What the Instructor Covered

1. Python Data Types – The Building Blocks

The session begins by introducing core data types under two broad categories:

  • Numbers (integers, floats, etc.)

  • Text (strings)

Understanding these types and how to manipulate them effectively is one of the first skills every Python developer should master.

2. Everything is an Object in Python

In Python, each object has three key properties:

  • Identity → A unique memory address (checked using id())

  • Type → Defines what kind of object it is (e.g., int, str, list)

  • Value → The actual data stored in the object

3. What is Mutability?

Mutable Objects

These objects can be modified after they're created.

Examples:

  • list

  • set

  • dict

Immutable Objects

Once created, these cannot be changed. Any update creates a new object in memory instead.

Examples:

  • int

  • float

  • string

  • tuple

4. Identity Matters More Than Value

The instructor stressed a powerful idea:

To understand mutability, don't just look at an object's value—always check its identity using id().

5. Real Examples That Made It Click

To show the difference clearly, the lecture included hands-on demos like:

  • Updating a number variable does not change the original object—Python creates a brand-new one in memory.

  • Using an everyday analogy—such as changing the sugar amount stored in a variable—beautifully illustrates how immutable values behave like rigid containers, while mutable ones act like editable jars.


Final Takeaway

Understanding mutable and immutable objects isn’t just theory—it's the foundation of writing smart, memory-efficient Python programs. This knowledge helps you avoid unexpected behavior when modifying data, especially inside functions or loops.

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