Top 50+ Python Interview Questions and Answers

Here is a curated list of 50+ Python Interview Questions and Answers for both beginners and experienced developers, categorized by topic:

1. Basic Python Questions

1. What is Python?
   • Python is a high-level, interpreted, and general-purpose programming language known for its simplicity and readability.
2. What are Python’s key features?
   • Easy-to-learn, open-source, dynamically typed, interpreted, portable, object-oriented, and supports extensive libraries.
3. What is PEP 8?
   • PEP 8 is a style guide for Python that ensures readable and consistent code.
4. What are Python’s data types?
   • Common types include int, float, str, list, tuple, dict, set, and bool.
5. How is Python an interpreted language?
   • Python executes code line by line without prior compilation, making it interpreted.

2. Data Structures in Python

6. Differentiate between lists and tuples.
   • Lists are mutable, whereas tuples are immutable.
7. What are Python sets?
   • Sets are unordered collections of unique items.
8. How do dictionaries work in Python?
   • Dictionaries store key-value pairs and provide fast lookups by key.
9. Explain list slicing.
   • Extract a sublist using the syntax list[start:end:step].
10. What is a Python frozenset?
    • An immutable version of a set.

3. Functions and Modules

11. What are Python functions?
    • Reusable blocks of code defined using the def keyword.
12. What are Python built-in functions?
    • Examples: len(), type(), sum(), min(), max().
13. What is a lambda function?
    • Anonymous functions created using the lambda keyword.
14. **What are *args and kwargs?
    • *args: Pass a variable number of positional arguments.
    • **kwargs: Pass a variable number of keyword arguments.
15. Explain Python modules and packages.
    • A module is a Python file, and a package is a collection of modules.

4. Object-Oriented Programming (OOP)

16. What is OOP in Python?
    • A programming paradigm that uses objects and classes to organize code.
17. Explain Python classes and objects.
    • A class is a blueprint for objects, and objects are instances of classes.
18. What are Python class attributes?
    • Variables shared across all instances of a class.
19. Explain the self parameter in Python.
    • Refers to the instance of the class and is used in instance methods.
20. What is inheritance in Python?
    • A mechanism to create a new class from an existing class.
21. What is polymorphism?
    • The ability of different objects to respond to the same method name.
22. What are Python decorators?
    • Functions that modify the behavior of other functions or methods.

5. Advanced Python Topics

23. What is a Python generator?
    • A function that returns an iterator using the yield keyword.
24. What are Python iterators?
    • Objects with __iter__() and __next__() methods.
25. What is the Global Interpreter Lock (GIL)?
    • A mechanism that allows only one thread to execute Python bytecode at a time.
26. What is Python’s garbage collection?
    • An automatic memory management system that removes unused objects.
27. What are Python’s built-in exceptions?
    • Examples: IndexError, KeyError, ValueError, TypeError.
28. What is the difference between shallow and deep copy?
    • Shallow copy creates a new object but references the original elements, while deep copy copies all objects recursively.

6. Libraries and Frameworks

29. What is NumPy?
    • A library for numerical computations and array manipulations.
30. What is Pandas?
    • A library for data manipulation and analysis.
31. What is Django?
    • A web development framework for building dynamic web applications.
32. What is Flask?
    • A lightweight web framework for creating simple applications.
33. What is TensorFlow?
    • A library for machine learning and deep learning tasks.

7. File Handling

34. How do you open a file in Python?
    • Using the open() function: open(filename, mode).
35. What are Python file modes?
    • Examples: r (read), w (write), a (append), rb (read binary).
36. How do you handle exceptions in file operations?
    • Use try, except, and finally blocks.
37. What is the with statement in file handling?
    • Ensures files are properly closed after operations.

8. Python Frameworks and Databases

38. What is SQLAlchemy?
    • An ORM tool for database operations in Python.
39. What is Pytest?
    • A framework for writing simple and scalable test cases.
40. How does Python connect to a database?
    • Using libraries like sqlite3 or MySQL Connector.

9. Miscellaneous

41. What is the Python GIL?
    • A lock that ensures thread safety in CPython but limits parallel execution.
42. What are Python comprehensions?
    • Concise ways to create lists, sets, or dictionaries, e.g., [x**2 for x in range(5)].
43. What is the difference between is and ==?
    • is checks object identity, while == checks value equality.
44. Explain Python’s slicing syntax.
    • Access specific parts of sequences like strings or lists using [start:end:step].
45. What is a metaclass?
    • A class that defines the behavior of other classes.
46. What is monkey patching in Python?
    • Dynamically modifying or extending code at runtime.
47. What is the __init__.py file?
    • Marks a directory as a Python package.
48. What are Python’s magic methods?
    • Special methods like __init__, __str__, and __len__.
49. Explain Python threading vs multiprocessing.
    • Threading runs threads within a single process; multiprocessing creates separate processes.
50. What is Python’s @staticmethod?
    • Defines a method that doesn’t need an instance or class reference.

51. Bonus Question

What are Python’s key advantages over other languages?

• Easy syntax, vast libraries, scalability, and extensive community support.

Let me know if you’d like examples for any question! 😊