Prepare for your Python interview with these top 50 Python interview questions and answers. Perfect for beginners and experienced developers.
1. What is Python?
Python is a high-level, interpreted, and general-purpose programming language known for its readability and ease of use.
2. What are Python’s key features?
Easy syntax, interpreted, dynamically typed, object-oriented, open-source, large standard library, and cross-platform support.
3. What are Python’s data types?
int, float, complex, str, list, tuple, dict, set, bool, bytes, etc.
4. What is the difference between list and tuple?
Lists are mutable and slower; tuples are immutable and faster.
5. What are Python dictionaries?
Unordered collections of key-value pairs.
6. What is PEP 8?
A style guide for writing clean and readable Python code.
7. Explain Python’s memory management.
Python uses reference counting and garbage collection.
8. What are Python namespaces?
A naming system to avoid name collisions. Types: local, global, built-in.
9. What is the difference between is and ==?is checks identity, == checks equality.
10. What are Python modules and packages?
Modules are .py files; packages are folders with __init__.py.
11. How does Python handle exceptions?
Using try-except-finally blocks.
12. What is the difference between @staticmethod and @classmethod?@staticmethod doesn’t take self or cls; @classmethod takes cls.
13. What are Python decorators?
Functions that modify other functions’ behavior.
**14. What are *args and kwargs?
*args: variable number of positional arguments; **kwargs: keyword arguments.
15. What is list comprehension?
A compact way to create lists:
[x for x in range(5)]
16. Explain Python generators.
Functions that yield values one at a time using yield keyword.
17. What are iterators and iterables?
Iterable: an object you can iterate over. Iterator: uses __iter__() and __next__().
18. What is the use of with statement in Python?
Simplifies exception handling and resource management (e.g., file handling).
19. What is lambda in Python?
Anonymous function written as lambda args: expression.
20. Difference between deepcopy and copy?copy() is shallow; deepcopy() copies nested objects as well.
21. What is Python’s GIL (Global Interpreter Lock)?
A mutex that allows only one thread at a time to execute in the interpreter.
22. What are Python’s built-in data structures?
List, Tuple, Set, Dictionary.
23. What is the difference between range() and xrange()?xrange() exists in Python 2; range() in Python 3 returns a generator-like object.
24. What are Python’s file modes?
‘r’, ‘w’, ‘a’, ‘rb’, ‘wb’, etc.
25. What is pickling in Python?
Serialization of objects using pickle module.
26. How do you manage packages in Python?
Using pip: pip install package_name
27. What are Python’s standard libraries?
os, sys, datetime, math, random, json, re, etc.
28. What is Python’s __init__.py used for?
It indicates a directory is a package.
29. Explain Python’s __name__ == "__main__" idiom.
Checks if the script is run as the main program.
30. What are Python docstrings?
Strings used for documentation, written using triple quotes.
31. What is a Python virtual environment?
Isolated environment for dependencies. Use venv or virtualenv.
32. Difference between mutable and immutable types?
Mutable: list, dict, set; Immutable: int, str, tuple.
33. What is duck typing in Python?
Type is determined by behavior rather than inheritance.
34. How do you handle memory leaks in Python?
Use profiling tools and avoid circular references.
35. How do you handle exceptions in Python?
try-except, optionally with else and finally.
36. What is multithreading and multiprocessing in Python?
Multithreading is limited by GIL; multiprocessing runs on multiple cores.
37. Explain Python’s map(), filter(), and reduce() functions.
Functional tools for applying functions to iterables.
38. What is the use of zip() function?
Combines iterables element-wise.
39. What are f-strings in Python?
Formatted string literals introduced in Python 3.6: f"Hello {name}"
40. What are Python type hints?
Optional annotations for variable and function types.
41. What is the purpose of pass, continue, and break?
pass: does nothing; continue: skips to next iteration; break: exits loop.
42. Explain slicing in Python.
Used to extract elements: list[start:end:step]
43. What is the difference between isinstance() and type()?isinstance() checks type hierarchy; type() checks exact type.
44. What are metaclasses in Python?
Classes of classes that define behavior of class creation.
45. How to handle memory optimization in Python?
Use generators, avoid large objects, use __slots__.
46. What is monkey patching?
Dynamic modification of classes or modules at runtime.
47. What is the difference between assert and exceptions?assert is used for debugging, exceptions are for error handling.
48. What is the nonlocal keyword?
Allows access to a variable in the nearest enclosing scope that is not global.
49. What are Python’s common testing frameworks?
unittest, pytest, doctest.
50. What are some common Python interview coding challenges?
Palindrome check, Fibonacci series, sorting, recursion problems, linked list operations.
