Top Python Interview Questions

Here are some common Python interview questions that span a range of topics:

Basic Questions

General Python Knowledge

  1. Difference between List and Tuple: How do lists and tuples differ in Python, and when might you choose to use one over the other?
  2. Mutability: What does it mean for an object to be mutable? Can you give examples of mutable and immutable objects?
  3. List Comprehensions: Can you provide an example of a list comprehension and explain how it works?
  4. Memory Management: How does memory management work in Python? What is garbage collection?
  5. Global and Local Variables: Explain the difference between global and local variables in Python.

Data Structures

  1. Dictionaries: How do you merge two dictionaries in a single expression?
  2. Sets: How can you remove duplicate elements from a list using sets?
  3. Data Types: Can you name and describe the standard data types in Python?
  4. Lambda Functions: Provide an example where a lambda function can be useful.

Object-Oriented Programming

  1. Classes/Objects: How are classes and objects related?
  2. Inheritance: How can a subclass be derived from a base class in Python?
  3. Encapsulation: Explain how encapsulation is implemented in Python.
  4. Polymorphism: How is polymorphism implemented in Python?

Web Development

  1. Flask and Django: What are the main differences between Flask and Django?
  2. HTTP Methods: What is the difference between the GET and POST HTTP methods?


  1. Unit Testing: How is unit testing performed in Python?
  2. Mocking: How and why might you use mocking in testing Python applications?

Concurrency and Parallelism

  1. Threads: How is threading implemented in Python, and what are its limitations?
  2. AsyncIO: What is the asyncio module used for, and how does it differ from multi-threading?

File Handling

  1. Reading Files: How do you read from a file in Python?
  2. Writing to Files: How can you write data into a file?

Error and Exception Handling

  1. Try/Except: How do you catch exceptions in Python?
  2. Custom Exceptions: How can you define custom exception classes in Python?

Python Libraries and Frameworks

  1. NumPy: Why might you choose to use NumPy arrays instead of nested Python lists for numerical computation?
  2. Pandas: How would you handle missing data in a Pandas DataFrame?
  3. TensorFlow/PyTorch: Can you name some differences between TensorFlow and PyTorch?

Python 2 vs Python 3

  1. Differences: Name some key differences between Python 2 and Python 3.
  2. Migration: What are some challenges when migrating code from Python 2 to Python 3?

PEP 8 and Code Style

  1. PEP 8: What is PEP 8 and why is it important?
  2. Docstrings: How should docstrings be formatted according to PEP 257?

Advance Questions

Memory Management and Optimization

  1. Memory Leaks: How can you identify and prevent memory leaks in Python?
  2. Object Interning: What is object interning, and how does it work in Python?


  1. Descriptors: How are descriptors used in Python and why might you use them?
  2. Metaclasses: What is a metaclass, and how/why would you use one?

Concurrency and AsyncIO

  1. GIL: Explain the Global Interpreter Lock (GIL) and its impact on multi-threaded Python programs.
  2. Async/await: How does the async/await syntax work under the hood?
  3. Event Loop: How does the event loop work in an async framework?

Decorators and Generators

  1. Decorators: How would you implement a decorator that measures the execution time of a function?
  2. Generators: How do generators work, and how are they different from functions?

Data Structures and Algorithms

  1. Algorithm Optimization: Can you optimize this algorithm further in terms of time and space complexity?
  2. Custom Data Structures: How would you implement [specific data structure] from scratch?


  1. Test Fixtures: How would you use fixtures in pytest?
  2. Mock: How do you use the unittest.mock library to mock objects in unit tests?

Web Development (Flask/Django)

  1. Middleware: How is middleware implemented in Django or Flask?
  2. ORM: How does the Django ORM work, and how can queries be optimized?


  1. Database Connection Pooling: How do you manage database connections and implement connection pooling?
  2. Normalization: Discuss database normalization and denormalization, and where might denormalization be useful.

Design Principles and Patterns

  1. Singleton Pattern: How would you implement a singleton pattern in Python?
  2. Factory Pattern: Can you provide an example of using the Factory design pattern in Python?

Distributed Systems and Scalability

  1. Scalability: How would you scale a Python web application?
  2. Caching Strategies: How would you implement caching to improve the performance of a Python application?


  1. Secure Data Storage: How would you securely store sensitive information in a Python application?
  2. Input Sanitization: What steps would you take to validate and sanitize user input in a web application?

Python C-API and Extensions

  1. Cython: How would you use Cython to speed up Python code?
  2. C Extensions: How can Python be extended with C code, and why might you do this?

Cloud and DevOps

  1. Docker: How would you containerize a Python application using Docker?
  2. CI/CD: How would you set up a CI/CD pipeline for a Python application?

Machine Learning

  1. Model Deployment: How would you deploy a machine learning model developed with Python into production?
  2. Data Pipelines: How would you design a robust and scalable data processing pipeline?

Remember that advanced questions may also require a demonstration of hands-on coding skills, problem-solving abilities, and a deep understanding of system design principles. Always be prepared to back up your answers with practical examples and experiences.

Bonus: System Design and Algorithms

  • Algorithm Complexity: How do you determine and communicate the time and space complexity of an algorithm?
  • System Design: How might you design a scalable and robust system using Python (e.g., a web API, a data pipeline, etc.)?

Feel free to adapt these questions to your needs and always be ready to provide or explore practical examples to showcase or enhance understanding!

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