Top 17 Python Interview Questions Every Backend Engineer Should Master

Today we share the first article in a Python interview question series, aiming to help job seekers and newcomers assess their knowledge gaps.

1. What does the pass statement do? It does nothing and serves as a placeholder.

2. How does Python perform type conversion? Built‑in functions like int() convert compatible strings to integers, otherwise an error is raised.

3. How does Python manage memory? Python uses a memory‑pool mechanism called Pymalloc to allocate and free small memory blocks efficiently.

4. Difference between dict.items() and dict.iteritems() ? items() returns a list of key‑value pairs (order not guaranteed), while iteritems() returns an iterator.

5. What is a lambda function and its benefit? A lambda is an anonymous, single‑line function useful when a named function is unnecessary; it can accept any number of arguments but must contain a single expression.

6. Differences between os and sys modules and common methods.

The os module provides a portable way to use operating‑system‑dependent functionality.

The sys module gives access to interpreter variables and functions that interact closely with the interpreter.

7. How to copy an object? Difference between copy and deepcopy . copy duplicates only the object itself; deepcopy also recursively copies referenced objects.

8. Difference between os.path and sys.path . os.path is a module with functions for pathname manipulation; sys.path is a list of directory strings that Python searches for modules.

9. Difference between re.match and re.search . match() checks for a match only at the start of the string, while search() scans the entire string.

10. How do generators differ from regular functions and a simple example. Functions use return to output a value and terminate; generators use yield to produce a value and pause execution, resuming later from the same point.

11. Relationship between WSGI and FastCGI. Both are CGI‑style interfaces; FastCGI is a long‑living, language‑agnostic extension that keeps processes in memory for better performance. WSGI (Python Web Server Gateway Interface) is the Python‑specific standard for connecting web servers and applications.

12. Differences between Django and Tornado. Django is a full‑stack, MVC‑style framework emphasizing rapid development and code reuse, while Tornado is a non‑blocking, high‑performance web server suitable for real‑time services.

13. How to use django‑debug‑toolbar . Add 'debug_toolbar.middleware.DebugToolbarMiddleware' to MIDDLEWARE_CLASSES in settings.py.

14. Using Redis as a cache in Django. Install the redis‑for‑django plugin, configure it in settings.py, and then use it as the cache backend.

15. How to run Django unit tests.

$ python manage.py test

$ python manage.py testanimals.tests

$ python manage.py testanimals

$ python manage.py testanimals.tests.AnimalTestCase

$ python manage.py testanimals.tests.AnimalTestCase.test_animals_can_speak

$ python manage.py testanimals/

$ python manage.py test--pattern="tests_*.py"

$ python -Wall manage.py test

16. Overview of the HTTP protocol. HTTP is an application‑layer, stateless, request/response protocol that is simple, fast, flexible, and connection‑less.

17. Common HTTP request headers and response status codes. Headers include Accept, Accept-Charset, Accept-Language, Accept-Encoding, Cache-Control, Connection, Content-Type, Cookie. Status codes are grouped as 1xx (informational), 2xx (success), 3xx (redirection), 4xx (client error), and 5xx (server error), with examples such as 200 OK, 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found, 500 Internal Server Error, 503 Service Unavailable.

Author: 地球的外星人君 Source: https://zhuanlan.zhihu.com/p/28122476