Preparing for a Python full stack interview? These detailed questions and answers will help you gain confidence and improve your chances of success. From Python fundamentals to frameworks, front-end integration, databases, and DevOps, we’ve covered it all.
1. Python Core Concepts
1. What are the key features of Python?
Python is an interpreted, high-level, dynamically typed language known for its readability and simplicity. It supports object-oriented, functional, and procedural programming, and has a rich standard library with powerful frameworks.
2. Explain Python’s memory management.
Python uses automatic memory management with reference counting and a cyclic garbage collector to free memory occupied by unused objects.
3. What is the difference between a list and a tuple in Python?
- Lists are mutable (can be modified), while tuples are immutable (cannot be changed).
- Lists use more memory but offer more flexibility. Tuples are faster and suitable for read-only data.
4. What is a Python decorator?
A decorator is a function that takes another function as input and extends or modifies its behavior without changing the function’s source code.
5. What are *args and kwargs?
*argsallows a function to accept any number of positional arguments.**kwargsallows a function to accept any number of keyword arguments.
6. What is the difference between deep copy and shallow copy?
- A shallow copy creates a new object but references the same nested objects.
- A deep copy creates new copies of all nested objects recursively.
7. How does exception handling work in Python?
Python uses try, except, finally, and else blocks to handle exceptions. You can catch specific exceptions or use a general exception handler.
8. What is the difference between is and ==?
==compares values.ischecks for object identity (whether two variables point to the same memory location).
2. Object-Oriented Programming in Python
9. What are the core principles of OOP?
- Encapsulation: Binding data and methods together.
- Inheritance: Acquiring properties of a parent class.
- Polymorphism: Multiple forms of a method.
- Abstraction: Hiding implementation details.
10. How does inheritance work in Python?
Python supports single, multiple, and multilevel inheritance. Child classes can override or extend parent class functionality.
11. What is method overriding?
Method overriding occurs when a subclass defines a method with the same name as a method in the parent class to provide specific behavior.
12. Difference between class method and static method?
- Class methods use
@classmethodand takeclsas the first argument. - Static methods use
@staticmethodand do not access class or instance variables.
13. What are magic methods in Python?
Magic methods (dunder methods) are special methods like __init__, __str__, and __len__ that define how objects behave with built-in operations.
3. Django and Flask (Back-End Frameworks)
14. What is Django and why is it used?
Django is a high-level Python web framework that enables rapid development and clean, pragmatic design. It includes built-in features like authentication, ORM, and admin panels.
15. What is Django ORM and how does it work?
Django ORM allows you to interact with databases using Python code instead of SQL. It maps database tables to Python classes.
16. How are forms handled in Django?
Django provides both built-in form handling via forms.Form and model-based forms using ModelForm. It includes validation and rendering capabilities.
17. Compare Django and Flask.
- Django is a full-stack framework with built-in tools.
- Flask is lightweight and flexible, suitable for microservices or when custom implementations are needed.
18. How do you handle migrations in Django?
Use makemigrations to create migration files and migrate to apply them to the database. Migrations track schema changes.
19. How do you secure a Django application?
Enable built-in middleware, validate inputs, use CSRF tokens, hash passwords, and enforce HTTPS.
20. What is Flask and how is it different from Django?
Flask is a minimalist framework that gives developers more control over components. Unlike Django, it does not include built-in ORM or admin interface by default.
4. Front-End Integration
21. How do you connect a React frontend with a Django backend?
Use Django REST Framework to create APIs and fetch data on the React frontend using HTTP requests like fetch() or axios.
22. What is the virtual DOM in React?
The virtual DOM is a lightweight copy of the real DOM that React uses to optimize updates by comparing versions before applying changes.
23. How does two-way binding differ from one-way binding?
- One-way binding: Data flows from model to view (e.g., React).
- Two-way binding: Data flows in both directions (e.g., Angular).
24. What is the role of state in React?
State holds data that can change over time. When state changes, React re-renders the component.
25. How do you manage forms in React?
Using controlled components where form values are bound to state variables. onChange handlers update state.
5. Database and API Integration
26. What databases are commonly used with Django?
PostgreSQL, MySQL, SQLite, and Oracle. PostgreSQL is preferred for production due to its performance and features.
27. What is REST API and how is it implemented in Django?
REST API allows communication via HTTP verbs. In Django, use Django REST Framework to create serializers and viewsets for CRUD operations.
28. How do you handle pagination in a Django REST API?
Use PageNumberPagination or LimitOffsetPagination classes provided by Django REST Framework.
29. What are serializers in Django REST Framework?
Serializers convert complex data types like querysets into JSON for API responses and vice versa.
30. How do you perform CRUD operations in Django?
Create models, use Django ORM for queries, and build views/forms or APIs to handle create, read, update, and delete.
6. Authentication and Authorization
31. How does token-based authentication work?
After login, a token (e.g., JWT) is generated and stored client-side. It’s included in request headers for authorization.
32. How do you manage user sessions in Django?
Django uses a session framework to store session data on the server side. Sessions can be stored in the database or cache.
33. What is CSRF and how is it prevented?
Cross-Site Request Forgery is an attack where unauthorized commands are submitted. Django prevents this using CSRF tokens in forms.
34. How can you restrict access to certain views in Django?
Use decorators like @login_required, @permission_required, or custom middleware.
7. Testing and DevOps
35. How do you write unit tests in Django?
Use Django’s TestCase class and run tests using python manage.py test. Use assertions to validate behavior.
36. What is continuous integration (CI)?
CI is the practice of automatically testing and integrating code changes into a shared repository, often using tools like GitHub Actions or Jenkins.
37. What is Docker and why is it useful in web development?
Docker containerizes applications, ensuring consistency across development and production environments. It simplifies deployment.
38. How do you deploy a Django application?
Common platforms include Heroku, AWS, and DigitalOcean. Use Gunicorn as WSGI and Nginx as a reverse proxy. Apply migrations and configure environment variables.
39. What is environment management and how is it done in Python?
Use virtual environments (venv, virtualenv, or pipenv) to isolate dependencies for different projects.
40. How do you monitor a deployed application?
Use tools like Sentry, Prometheus, or New Relic for error tracking, performance monitoring, and logging.
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