Services
Technology Web App Development Mobile App Development Windows App Development Database Development UI/UX Development Cloud Development SEO Digital Marketing Guest Posting Content Writing Artificial Intelligence Data Science ERP Development CRM Development CMS Development LMS Development Business Listing Blockchain Technology Startup Promotion AI Tools Integration
Products
Data Converter Cleaner TUC - Unit Converter Import Export Survey Manager Tweet Controller
Developer
Article Blog Forum Interview Beginner News Startup Quiz
Users
Career
Apply Job Internship
Pricing
Login Sign Up Get a Quote

interview

Home Interviews What is the difference between mutable and immutable types in Python? – MindStick
Ask Question

1 Answers

ICSM Computer
ICSM Computer 27 Mar 2025
Report Abuse

Mutable vs Immutable Types in Python

In Python, mutability refers to whether an object can be changed after it is created. Based on this, Python data types are classified as:

  1. Mutable → Can be modified after creation.
  2. Immutable → Cannot be modified after creation.

Mutable Types (Can Change)

These objects allow modifications without changing their identity (memory location).

Examples of Mutable Types

  1. list
  2. dict (dictionary)
  3. set
  4. bytearray

Example of a Mutable List

numbers = [1, 2, 3]
print(id(numbers))  # Memory address before modification

numbers.append(4)   # Modify list
print(numbers)      # [1, 2, 3, 4]
print(id(numbers))  # Memory address remains the same

Immutable Types (Cannot Change)

Once an object is created, it cannot be modified. Any modification creates a new object in memory.

Examples of Immutable Types

  1. int
  2. float
  3. bool
  4. tuple
  5. str
  6. frozenset
  7. bytes

Example of an Immutable String

name = "Hello"
print(id(name))  # Memory address before modification

name += " World"  # Attempting to modify
print(name)      # "Hello World"
print(id(name))  # Memory address changes (new object created)

Key Differences Between Mutable and Immutable Types

Feature Mutable Types (Changeable) Immutable Types (Unchangeable)
Modification Can be modified in place Cannot be modified once created
Memory Usage Same object remains in memory New object is created on change
Examples list, dict, set int, float, str, tuple
advertising
Markdown for AI

A clean, structured version of this page for AI assistants and LLMs.

Open .md