What Python Developers can expect at a technical interview

Python is one of the most sought-after programming languages in the tech industry, making Python Developers highly valuable assets for companies.

Python Developer technical interviews are hybrid

If you’re preparing for a technical interview as a Python Developer, you can expect a mix of theoretical questions, coding challenges, and system design problems.

Here’s a breakdown of the types of questions you might face and how to prepare for them effectively, writes Ben Quinn, head of technology recruitment at Leap29.

1. Basic and Core Python Questions – top 7 openers at interview

These initial questions test your understanding of Python fundamentals and syntax.

You may be asked these seven questions:

1. What are Python’s key features?

2. Explain the difference between Python 2 and Python 3.

3. How is Python an interpreted language?

4. What are Python’s built-in data types?

5. How do you manage memory in Python?

6. What is the difference between mutable and immutable data types?

7. Explain list comprehension with an example.

2. Object-Oriented Programming (OOP) in Python – 5 testing FAQs

Python is an object-oriented language, so many interviews will assess your knowledge of OOP principles.

Related to these, prepare to face these five Frequently Asked Questions (or variants of them):

• What are classes and objects in Python?

• Explain the concepts of inheritance, polymorphism, encapsulation, and abstraction.

• How do you implement method overloading and method overriding in Python?

• What is the difference between @staticmethod, @classmethod, and an instance method?

• How do you achieve multiple inheritance in Python?

3. Data Structures and Algorithms – six key areas at job interview

A strong grasp of data structures and algorithms is essential for any Python Developer.

Therefore, expect questions on these six areas:

i. Implementing sorting algorithms (Bubble Sort, Quick Sort, Merge Sort, etc.).

ii. Searching algorithms (Binary Search, Linear Search).

iii. Understanding and using data structures like lists, tuples, sets, and dictionaries.

iv. Implementing stacks, queues, linked lists, trees, and graphs in Python.

v. Time and space complexity analysis using Big-O notation.

vi. Solving coding problems like finding duplicates in a list or reversing a linked list.

4. Python Libraries and Frameworks – 5 technical test questions

Depending on the specifics of the role (but regardless of whether it is contract or full-time), you may be asked about Python libraries.

Being comfortable if asked the following five questions is therefore recommended:

1. What are some common Python libraries used for data analysis?

2. How does NumPy differ from Pandas?

3. How do you use Flask or Django for web development?

4. Explain the purpose of TensorFlow and PyTorch in machine learning.

5. How does BeautifulSoup or Scrapy work for web scraping?

5. File Handling & Exception Handling: 5 Developer queries

Handling files and exceptions is crucial for robust applications.

Python developers should therefore expect to be on the receiving end of these five queries:

• How do you open, read, and write files in Python?

• What is the difference between ‘r’, ‘w’, ‘a’, and ‘r+’ modes?

• How do you handle exceptions in Python using try-except blocks?

• Explain the use of finally and else clauses in exception handling.

• What are custom exceptions, and how do you create them?

Multithreading and Concurrency – 4 inquiries often asked at interview

Some roles that contractors or full-timers skilled in Python go forward and apply for can require knowledge of threading and asynchronous programming.

So, rehearse your answers to these four technical inquiries before you receive them at interview:

i. What is the difference between threading and multiprocessing?

ii. How does Python’s Global Interpreter Lock (GIL) affect multithreading?

iii. What is the asyncio module used for?

iv.  How do you use locks in multithreading?

7. Database and ORMs: four or five technical test probes…

Many Python applications interact with databases, so expect interest in SQL and ORMs to be at least four-fold.

1. How do you connect Python to a database?

2. What is the difference between SQL and NoSQL databases?

3. How does Django’s ORM work?

4. What are transactions in databases, and how do you handle them in Python?

8. System Design and Scalability Questions: a quartet of queries

For senior roles requiring Python, you may be asked at interview or technical test about designing scalable systems.

As a result, be across this quartet before it gets fired at you:

• How would you design a URL shortener like Bit.ly?

• How do you handle a million requests per second in a Python application?

• What are microservices, and how do you implement them in Python?

• How do you use caching mechanisms in Python?

9. Testing and Debugging: job interviewers like to ask these four…

Testing is an essential part of software development.

A well-prepared Python job candidate won’t therefore be fazed by the interviewer posing these four:

i. What are different types of testing in Python?

ii. How do you write unit tests in Python?

iii. What is the difference between unittest and pytest?

iv. How do you debug a Python program effectively?

By my count, that’s 45 questions that wannabe Python Developers should be ready to answer at a technical interview or test.

But very often, and partly because Python is now the main technical skill asked of contractors vying for cutting-edge AI roles, it’s not just questions or queries.

10. Live Coding Challenges: Be ready to face these five

Most technical interviews you’ll face as a Python Developer will have a live coding session, where you may be asked any or all of these five:

Ø  Reverse a string without using built-in functions.

Ø  Find the longest substring without repeating characters.

Ø  Implement a LRU (Least Recently Used) cache.

Ø  Parse a log file and extract useful insights.

Ø  Solve problems from platforms like LeetCode or HackerRank.

Python Developer: How to prep for technical interview – 5 must-dos

1. Practice coding: Use sites like LeetCode, HackerRank, and CodeSignal.

2. Understand Python deeply: Don’t just memorise; understand how things work.

3. Build projects: Hands-on experience will help reinforce concepts.

4. Mock interviews: Practice solving problems under time constraints.

5. Review Python documentation: Keep up with the latest Python updates.

TLDR: Python Developer job interview preparation be like…

A technical interview for a Python Developer is typically five-fold; it will assess your knowledge of core Python, algorithms, data structures, libraries, and system design.

By preparing thoroughly and practising up-to-the-minute coding problems – while rehearsing your answers aloud, you can increase (and then even optimise) your chances of securing your desired Python Developer role.