The Top 3 Python Interview Questions (and How to Answer Them!)

Table of Contents

• Meet the Expert: Nate Welter
• Python Interview Questions by Industry
• 3 Typical Python Topics in Interviews
• 1. A Conceptual Python Question
• 2. A Question about Implementing Python Code
• 3. An Object Oriented Programming (OOP) Question
• How to solve a Python whiteboard problem in an interview
• Typical Python Interview Questions for Every Stage of Your Python Career
• Preparing for Python Interviews at Coding Temple

Worried about nailing your Python technical interview? Nate Welter, Technical Instructor at Coding Temple, is sharing the top 3 Python interview questions you should be prepared to respond to in 2022. Learn how to break down any of these Python interview questions, and the best ways to prepare yourself with Nate’s tips and resources. Plus, find out how the new Technical Career Support Program at Coding Temple gives graduates an edge in their Python interviews.

Meet the Expert: Nate Welter

• Nate started as a Teacher’s Assistant at Coding Temple in 2020, then has since become a full-time Python instructor. 
• Nate is now an Alumni Technical Instructor, guiding graduates with technical career support, and becoming a technical interview expert on the behalf of Coding Temple graduates.

Python Interview Questions by Industry

First of all, the questions you hear in an interview will vary by industry. Python is a back-end language, but can be used in web development, software engineering, data analysis, data engineering, and data science. Before the interview, look through your projects and choose past work in the context of the industry.

For example, an API project would make sense for a web developer job interview. A data scraping project would be a great example to share in a data-centric job interview.

Regardless of the industry, my advice to stand out in any Python interview is to talk to your interviewer!

3 Typical Python Topics in Interviews

Interview questions will vary depending on the company, but there are three topics or types of questions you might be asked in a Python interview. 

1. A Conceptual Python Question

Expect one lower-level, conceptual Python. On the job, you’ll need to know syntax and how to write a program, but this question will ask you to explain how the computer is actually registering the code. 

Example Question: “Does Python pass arguments by reference or by value?”

How to solve this question: Break the larger conceptual problem down into smaller parts. 

• Explain the definition of an argument. As a programmer, you know what an argument is – data that you pass into a function. In Python, all arguments are passed by object reference, which means if we are altering some sort of argument from inside of a function, those changes will also occur to that data that's stored outside of the function.
• Explain the definition of a reference. A reference is a variable name that refers to some workable data.
• What is a value? A value is an actual number or physical hard data.
• Put all of this information together and this interview question is asking: Are the arguments passed into a function, passed by the reference to the place and memory, or just a copy of the values?

Tip for solving this question: Study! Go to realpython.com for Python documentation and PEP 8 styling standards. While in the interview, you can break questions down and ask clarifying questions to try to get to the correct answer, but when a question centers around technical terminology, you either know it or you don’t. 

2. A Question about Implementing Python Code

Python has specific syntax and built-in functionalities, so if you are interviewing for a Python-specific development role, you will need to know how to implement certain things.

Sample Interview Questions:  

• What is list comprehension and can you give an example?
• Create a list with even numbers from zero to 10 using Pythonic syntax. 

Tip for solving this question: While a Python code implementation question can be answered creatively, the purpose of this type of question is to draw out a specific sort of solution. Make sure you prepare for all possible ways that this question can be asked!

If you’re stuck on a Python-specific syntax question, rather than saying, “I don’t know,” you might say "I'm not too familiar with this specific method you're asking about, but from what I know about this data structure, I'm assuming it does this..." 

3. An Object Oriented Programming (OOP) Question

Object oriented programming (OOP) is a design standard throughout the software development world. It’s a vital topic discussed in most software development interviews, but especially in Python development roles. In Python, it is the use of classes and having scalable, maintainable, and testable code. Most jobs require proficiency in object oriented design or programming and you could be asked about anything relating to OOP in an interview. 

Sample Interview Questions: 

• “Show me an example of inheritance in object-oriented programming.” 
• “Tell me about a time that you have used object-oriented design in a project.”

When answering OOP questions, you must know the four pillars of object-oriented programming:

1. Inheritance. An interviewer may also ask what inheritance is in a quick example in Python code.
2. Polymorphism. Working with inheritance, we can inherit data from a parent class and then make some sort of change to that, so we have reusability in our code.
3. Encapsulation. 
4. Abstraction.

Tip for solving this question: OOP is a rigid structure on its own, but there is room for creative solutions. In regards to OOP questions, have examples prepared for the four pillars of object-oriented programming and have 1-2 previous OOP projects that you’ve completed in mind. If you’ve worked with Flask, Django, or any sort of API, it should be relatively easy for you to talk about a past project in the interview. 

How to solve a Python whiteboard problem in an interview

One of the most important parts of the interview process and something I stress to all alumni leaving Coding Temple is to have a solid grasp on whiteboarding. Whiteboard challenges are a way to test your ability to code and problem-solve. The questions in the interview may be related to the role you’re applying for or it could be a question that tests your ability to use data structures and algorithms. 

Sample Whiteboarding Questions: 

• “Can you leverage built-in Python functionality, data structures, and algorithms to solve a problem from start to finish?”

3 Steps to Approach a Whiteboarding Problem

1. Break down the problem into the smallest steps you can and develop a roadmap for your solution before you even start coding. If you start coding immediately without thinking it through, you may forget something or get stuck in a place that is difficult to backtrack. Ask yourself: What is this question asking of me? What is the given input or argument? What is my expected output? What steps, line by line in Python, do I need to make in order to turn that input into the desired output every time? Pseudocode if you need to!
2. Ask your interviewer clarifying questions. If you're having trouble understanding any specific part of a question, ask as many clarifying questions as you can. The interviewer is expecting you to develop the most efficient solution, and you can’t do that without asking clarifying questions.
3. Talk your way through the interview. Your interviewer is interested in your ability to code, but they also want to see who you are as a person. An interviewer is trying to gauge what it would be like to have you working alongside them on the team, and if you’re good at communicating. By communicating, you will obviously convey your thought process to your interviewer, and it opens up the potential for hints. If you forget a piece of syntax but can explain what you’re trying to do, your interviewer may be more inclined to offer grace and aid since they knew what you were referring to.

Tips to Practice Whiteboarding: Utilize puzzle prompting sites like LeetCode and Codewars to practice whiteboarding. 

Typical Python Interview Questions for Every Stage of Your Python Career

Most Coding Temple bootcamp grads are qualified to apply for entry-level and mid-level Python developer roles, but if you’re curious about the trajectory of a Python career, here’s what to expect.

Entry-Level Python Interview

An entry-level Python applicant needs to have a solid foundation of programming fundamentals and syntax, and should understand Python data types. The biggest barrier to entry on an entry-level job is the volume of knowledge you need to have. You’ll need to know all about the rules, tools, and standard built-in data types in Python. 

Entry-level Python applicants should know:

• The difference between a list and a tuple.
• If a certain data type, such as a string, is mutable or immutable.
• Built-in Pythonic syntax, like a list comprehension or a lambda function.
• Standard programming concepts, like logical flow, for loop, while loop, and conditional statements.
• Object oriented design and have past projects prepared to showcase your experience with OOP. 

Less important on the job, but imperative for an interview, you want to have a solid grasp of the more common data structures and algorithms, and time-space complexity analysis of those data structures and algorithms. 

Mid-Level Python Interview

In addition to entry-level information, a mid-level interview consists of low-level, in-depth, computer science questions, like:

• How is memory managed with Python? 
• What is the global interpreter lock?
• Can we have concurrent programming?

Mid-level Python interviews may also consist of:

• Writing unit tests.
• Looking at a work project in the scope of the overall organization and how that function or piece of functionality fits within the scope of the website or software company. 
• Looking at a system design and the overall structure versus focusing on a specific item.   

Senior-Level Python Interview

A senior-level Python developer leans into managerial and mentorship roles. In mid-level interviews, it’s all about how to ask the right questions, while a senior-level interviewee knows how to answer those questions. Senior-level roles are focused on conceptual big-picture specifics, like how a team’s specific projects fit into the scope of the overall structure (organization, website, app, etc). The senior-level role may also be involved conceptualizing new features and additions to a site or software; building new ideas from the ground up since they understand how everything works. They often manage a team and are extremely well-versed in and can write elegant code and design. 

Applicable to all levels, Seniors are also highly interested in new tech, implementing new best practices, and updating legacy code from when they were a Junior developer. Seniors are on the front lines of learning and teaching new tech to their team. 

Preparing for Python Interviews at Coding Temple

During the 10-week bootcamp, Coding Temple prepares bootcampers with whiteboard challenges and devoted, in-depth Python curriculum, but often our bootcampers are still digesting this information after they graduate. Coding Temple developed a new Technical Career Support curriculum to ensure graduates retain that info and that they’re prepared for technical interviews. 

What does Coding Temple’s Technical Career Support curriculum include?

We’ve broken the curriculum into workshops, mock interviews, 1:1 coaching, whiteboard practice, and algorithm practice. 

• Workshops and Mock Interviews. First, we tackle data structure and algorithm workshops. Each week, we host two workshops dissecting a specific data structure, algorithm, or interview question pattern. Then we implement and practice so students feel prepared for whiteboard challenges in interviews. The curriculum also includes an interview debrief workshop, where every week, anyone who’s been in a technical interview shares their experience with Coding Temple staff so that we can aggregate new information to show incoming alumni what employers are looking for now. I take those interview questions and solve them on my own to determine the best way I could teach our students how to approach it. Every Friday, we have a round table discussion workshop where we review these questions, how others approached the topic, discuss what worked and didn’t work, and then I offer how I would do it. With all of this aggregated data from alumni, we are better able to tailor mock interviews to the specific tech stack our students are trying to get into. For someone specifically applying for front end roles, we can have a JavaScript or React interview. If they're going for back end roles, we could focus on interviewing with Python and APIs. We offer this interview support to all of our graduates, whether they are going into roles in data science, data analytics, or software engineering.
• Whiteboarding. At Coding Temple, we practice whiteboarding daily. Students take turns solving a whiteboard question in front of their cohort and they're expected to run through the steps: Talk through your solution as you plan it out, explain it to your cohort mates, and handle the pressure of being on the spot. For alumni, I post a daily challenge. It may be a problem I’ve made up or an interview question that one of the alumni got in the past week. I'll pose that question in our alumni Slack channel and people reply with their solution throughout the day. I'll nudge people toward more efficient solutions, and at the end of the day, I'll post my most efficient solution and break down how I approached it and why.
• Alumni Algorithm Nights. We host alumni algorithm nights every other week, where anyone that's ever graduated Coding Temple can join an 1.5 hour long Zoom call. During the session, we have 15-20 alumni work on this same whiteboard challenge in teams of 2-3 people. It's a great opportunity for people to collaborate, learn from each other, and talk through their solutions, with the added element of competition. There's a prize at the end for the first team to bring back the most efficient solution, then we discuss why this approach was best. 

Coming out of a bootcamp can be overwhelming as the job application process takes front seat. This course is a great way to keep challenging yourself daily, and stay up-to-date on evolving technology and applications that you can implement in your code or in an interview.

Find out more and read Coding Temple reviews on Course Report. This article was produced by the Course Report team in partnership with Coding Temple.