315 Essential Python Interview Questions to Master Your Skills

Part 1: Python Basics (80 questions)

Why learn Python?

How did you learn Python?

Compare Python with Java, PHP, C, C#, C++.

Explain interpreted vs compiled languages.

Describe Python interpreter types and their features.

What is the relationship between bits and bytes?

Explain the relationship between b, B, KB, MB, GB.

List at least five PEP8 conventions.

Convert binary to decimal: v = "0b1111011".

Convert decimal to binary: v = 18.

Convert octal to decimal: v = "011".

Convert decimal to octal: v = 30.

Convert hexadecimal to decimal: v = "0x12".

Convert decimal to hexadecimal: v = 87.

Write a function to convert an IP address to an integer (e.g., 10.3.9.12).

Combine the binary strings above and compute the decimal result.

What is the maximum recursion depth in Python?

Evaluate the following expressions:

v1 = 1 or 3
v2 = 1 and 3
v3 = 0 and 2 and 1
v4 = 0 and 2 or 1
v5 = 0 and 2 or 1 or 4
v6 = 0 or False and 1

Explain the differences between ASCII, Unicode, UTF‑8, and GBK.

Distinguish bytecode from machine code.

Explain the ternary operator and its use cases.

List differences between Python 2 and Python 3.

Swap two values in one line of code.

Difference between int and long in Python 3 vs Python 2.

Difference between xrange and range.

Difference between xreadlines and readlines.

Common values that evaluate to False.

Five common methods for strings, lists, tuples, and dictionaries.

Format and use cases of lambda expressions.

Purpose of the pass statement.

Purpose of *args and **kwargs.

Difference between is and ==.

Explain shallow vs deep copy and their scenarios.

Describe Python's garbage collection mechanism.

Mutable vs immutable types in Python.

Result of the following code:

v = dict.fromkeys(['k1','k2'],[])
v['k1'].append(666)
print(v)
v['k1'] = 777
print(v)

Result of the code shown in the image (question 31).

List five common built‑in functions.

Purpose of filter, map, reduce.

One‑line code to generate a 9×9 multiplication table.

How to install third‑party modules and which ones you have used.

List at least eight commonly used modules.

Difference between re.match and re.search.

Explain greedy matching in regular expressions.

Result of the following list comprehensions:

a. [i % 2 for i in range(10)]
b. (i % 2 for i in range(10))

Result of the following expressions:

a. 1 or 2
b. 1 and 2
c. 1 < (2==2)
d. 1 < 2 == 2

What pitfalls exist with a function defined as def func(a, b=[])?

Convert "1,2,3" to ['1','2','3'].

Convert ['1','2','3'] to [1,2,3].

Difference between a = [1,2,3] and b = [(1),(2),(3)] vs b = [(1,),(2,),(3,)].

One‑line code to generate [1,4,9,16,25,36,49,64,81,100].

One‑line code to remove duplicate values from a list.

How to set a global variable inside a function?

Purpose and use cases of the logging module.

Implement a stack using code.

Common string formatting methods.

Explain generators, iterators, iterable objects and their use cases.

Write a binary search function in Python.

Discuss your understanding of closures.

Purpose of os and sys modules.

How to generate a random number.

How to delete a file using Python.

Explain object‑oriented programming concepts.

Characteristics of inheritance in Python OOP.

Depth‑first vs breadth‑first traversal in OOP.

Purpose of super().

Have you used functions from functools? What do they do?

List special methods with double underscores (e.g., __new__, __init__).

How to distinguish a function from a method.

Difference between static methods and class methods.

List special members in OOP and their scenarios.

How many distinct three‑digit numbers can be formed from 1,2,3,4,5 without repetition?

What is reflection and its use cases?

Purpose and use cases of metaclasses.

Implement the singleton pattern using as many methods as possible.

Write decorators and explain their use cases.

Exception handling patterns and how to raise exceptions deliberately.

Explain Python's method resolution order (MRO).

Purpose and use cases of isinstance.

Part 2: Network Programming and Concurrency (34 questions)

Briefly describe the OSI seven‑layer model.

What are C/S and B/S architectures?

Explain the three‑way handshake and four‑way termination processes.

What is the ARP protocol?

Differences between TCP and UDP.

Define LAN and WAN.

Why is TCP‑based communication more reliable than UDP?

What is a socket? Outline the TCP socket communication flow.

What is packet sticking (粘包) and its causes?

Purpose of I/O multiplexing.

What is a firewall and its role?

Differences among select, poll, and epoll models.

Contrast processes, threads, and coroutines and their use cases.

What is the GIL?

How to use thread pools and process pools in Python.

Purpose of threading.local.

How do processes communicate with each other?

Define concurrency and parallelism.

Roles of process locks and thread locks.

Explain asynchronous non‑blocking I/O.

Difference between routers and switches.

What is domain name resolution?

How to modify the local hosts file?

Use cases and advantages of the producer‑consumer model.

What is CDN?

What is LVS and its function?

What is Nginx and its role?

What is keepalived and its purpose?

What is HAProxy and its function?

Define load balancing.

What is RPC and its use cases?

Briefly describe the asyncio module and its scenarios.

Briefly describe the gevent module and its scenarios.

Usage of the Twisted framework.

Part 3: Databases and Caching (46 questions)

List common relational and non‑relational databases.

Common MySQL storage engines and their comparisons.

Explain the three normal forms.

What is a transaction? How does MySQL support transactions?

One‑to‑many and many‑to‑many scenarios in database design.

How to implement a product counter in a shop using a database.

Essential SQL commands.

Explain triggers, functions, views, and stored procedures.

Types of MySQL indexes.

When does the left‑most prefix rule apply to indexes?

Difference between primary keys and foreign keys.

Common MySQL functions.

Eight cases where an index cannot be used.

How to enable slow query logging.

Database import/export commands (structure + data).

Database optimization strategies.

Difference between CHAR and VARCHAR.

Explain MySQL execution plans.

Explain the difference between the following two queries:

select * from tb where name = 'name1'
select * from tb where name = 'name1' limit 1

Why does pagination with LIMIT/OFFSET become slower on large tables and how to solve it?

What is index merge?

What is a covering index?

Explain read‑write splitting.

Explain sharding (horizontal and vertical).

Compare Redis and Memcached.

How many databases does Redis have by default and what are they for?

Python modules for operating Redis.

How to iterate over a very large Redis list.

How does Redis master‑slave replication work and synchronize data?

Purpose of Redis Sentinel.

How to implement a Redis cluster.

How many hash slots does Redis have by default?

Redis persistence strategies and their comparison.

List Redis expiration policies.

How to keep hot data in Redis when MySQL holds 20 M rows and Redis only 200 k rows.

Write code to implement FIFO, LIFO, and priority queues using Redis lists.

How to implement a message queue with Redis.

How to implement publish/subscribe with Redis and differences from a message queue.

What is Codis and its purpose?

What is Twemproxy and its purpose?

Write code to perform Redis transactions.

Purpose of the WATCH command in Redis.

Implement a product quantity counter for an e‑commerce site using Redis.

Explain Redis distributed lock and Redlock mechanism.

What is consistent hashing? Does Python have a module for it?

Efficiently find all keys starting with "find1" in Redis.

Part 4: Front‑end, Frameworks and Others (155 questions)

What is your understanding of the HTTP protocol?

What is your understanding of the WebSocket protocol?

Define a magic string.

How to create responsive layouts?

Which front‑end frameworks have you used?

What is an AJAX request? Implement one using jQuery and XMLHttpRequest.

How to implement polling on the front‑end?

How to implement long polling on the front‑end?

Purpose of Vuex.

Purpose of route guards in Vue.

Purpose of Axios.

List common Vue directives.

Explain JSONP and its implementation.

What is CORS?

List common HTTP request methods.

List HTTP status codes.

List common HTTP request headers.

Difference between is and == in Python.

How does Python manage memory?

Tools for debugging or static analysis.

What is a Python namespace?

Purpose of the pass statement in Python.

Difference between xrange and range.

Compare Django, Flask, and Tornado frameworks.

What is WSGI?

Django request lifecycle.

List built‑in Django components.

Five methods of Django middleware and their use cases.

Explain FBV and CBV.

When is the Django request object created?

How to add decorators to CBV programs?

List all methods of Django ORM QuerySet.

Difference between only and defer.

Difference between select_related and prefetch_related.

Difference between filter and exclude.

Three ways to write raw SQL in Django ORM.

How to set read‑write splitting in Django ORM.

Purpose of F and Q objects.

Difference between values and values_list.

How to bulk‑create data with Django ORM.

Purpose of Django Form and ModelForm.

Two ways to update choices in a Form field in real time.

Purpose of on_delete in a ForeignKey field.

How CSRF is implemented in Django.

How to implement WebSocket in Django.

How to send CSRF token with AJAX POST in Django.

How to log data insertion in Django ORM.

How to configure caching in Django.

Can Django cache use Redis? How to configure?

Purpose of the name attribute in Django routing.

Difference between filter and simple_tag in Django templates.

Purpose of Django Debug Toolbar.

How to write unit tests in Django.

Explain DB‑first vs code‑first in ORM.

How to generate model classes from database tables in Django.

Pros and cons of using ORM vs raw SQL.

Explain MVC vs MTV.

Purpose of Django contenttype component.

Understanding of RESTful conventions.

What does idempotent mean for an API?

What is RPC?

Difference between HTTP and HTTPS.

Why use Django REST framework?

Components of Django REST framework.

View classes that can be inherited in DRF.

Authentication flow in DRF.

How DRF implements request rate limiting.

Advantages of Flask framework.

Components Flask depends on.

Purpose of Flask blueprints.

List Flask third‑party extensions you have used.

Explain Flask context management flow.

Purpose of g in Flask.

Classes involved in Flask context management and their roles.

Why Flask maintains a stack for Local objects.

How Flask handles multiple apps.

Components needed to implement WebSocket in Flask.

Purpose of WTForms.

Default session handling mechanism in Flask.

Difference between Flask’s Local object and threading.local.

What is Blinker in Flask?

Difference between Session and scoped_session in SQLAlchemy.

How to execute raw SQL in SQLAlchemy.

How ORM works.

Purpose of DBUtils module.

Correct the following SQLAlchemy field definitions:

from datetime import datetime
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, DateTime
Base = declarative_base()
class UserInfo(Base):
    __tablename__ = 'userinfo'
    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(64), unique=True)
    ctime = Column(DateTime, default=datetime.now())

How to set engine and character set for a table in SQLAlchemy.

How to define composite unique indexes in SQLAlchemy.

Describe characteristics of the Tornado framework.

Purpose of Future objects in Tornado.

How to write a WebSocket program with Tornado.

How Tornado serves static files.

Modules used by Tornado to operate MySQL.

Modules used by Tornado to operate Redis.

Typical use cases for Tornado.

Common Git commands and their purposes.

Purpose of git stash and related commands.

Difference between git merge and git rebase.

How companies collaborate using Git.

How to conduct code review with Git.

How to manage version tags like v1.0, v2.0 in Git.

What is GitLab?

Difference between GitHub and GitLab.

How to contribute to open‑source projects on GitHub.

Purpose of .gitignore file.

What is agile development?

Purpose of Jenkins tool.

How companies perform code deployment.

Differences among RabbitMQ, Kafka, and ZeroMQ.

How RabbitMQ ensures data is not lost if a consumer crashes before processing.

How RabbitMQ persists messages.

How RabbitMQ controls message consumption order.

Meanings of RabbitMQ exchange types: fanout, direct, topic.

What is Celery and its use cases.

How Celery works.

How Celery implements scheduled tasks.

Structure of a Celery multi‑task project.

Difference between @app.task and @shared_task decorators.

Purpose and basic usage of the requests module.

Purpose and basic usage of BeautifulSoup.

Purpose and basic usage of Selenium.

Workflow of components in Scrapy framework.

How to set proxies in Scrapy (two methods).

How to download large files with Scrapy.

How to implement rate limiting in Scrapy.

How to pause a Scrapy spider.

How to create custom Scrapy commands.

How Scrapy records crawl depth.

How Scrapy pipelines work.

How to discard an item in Scrapy pipelines.

Purpose of spider middleware and downloader middleware in Scrapy.

Purpose of scrapy‑redis component.

How scrapy‑redis deduplicates tasks.

How scrapy‑redis scheduler implements depth‑first and breadth‑first.

Explain virtualenv and its use cases.

Explain pipreqs and its use cases.

Python code analysis tools you have used.

Purpose of configuration management tools: SaltStack, Ansible, Fabric, Puppet.

Difference between B‑Tree and B+‑Tree.

List common sorting algorithms and implement any three.

List common searching algorithms and implement any three.

List design patterns you are familiar with.

Have you used LeetCode?

List common Linux commands you know.

What operating system runs on your company's production servers?

Explain PV and UV.

Explain QPS.

Difference between uWSGI and WSGI.

Purpose of Supervisor.

What is a reverse proxy?

Explain the entire SSH process.

Where do you look for solutions when you encounter problems?

Do you follow any tech‑related public accounts?

What new technologies are you currently researching?

Are you familiar with domain‑driven design?