Python, now among the most popular programming languages, is becoming increasingly important in software development, data science, and web development. From the development of web applications and websites to the creation of complex data models, Python offers various tools that developers can use in any project. The applications are far-ranging, and it is for this reason that Python developers are highly sought after in today’s tech industry.
If your company is among those looking to hire a Python developer, you're probably preparing for interviews. But hiring a Python developer may require more than just asking basic interview questions. This article will provide you with carefully selected Python interview questions and sample answers that will help you evaluate a potential candidate.
What Is a Python Developer?
According to Coursera, a Python developer is a software developer who specializes in writing code for applications and websites with the Python programming language. They design, code, debug, maintain and document projects, and utilize open-source libraries and tools.
A Python developer can be a software engineer, a data scientist, or a web developer. They use Python to create applications and websites, develop software prototypes, and create data models. Depending on the type of job they have, their responsibilities may vary as follows:
Python Software Engineer Responsibilities
- Define application objectives and design software solutions
- Write high-quality source codes and analyze and debug existing code
- Develop unit tests to identify potential software issues
- Collaborate with other developers to create robust applications
Python Data Scientist Responsibilities
- Analyze complex data sets and devise solutions
- Create data models and algorithms to solve business problems
- Design and execute experiments to validate hypothesis
- Develop automated tools to monitor data quality
Python Web Developer Responsibilities
- Write high-quality source codes in Python for web applications
- Create user interfaces and back-end components
- Test and debug web applications
- Develop unit tests to ensure product quality
Be sure to clearly list all the responsibilities, required skills, and education when creating a job listing. A compelling and in-depth Python developer job description will help you attract top talent, ensuring only the best candidates move on to the interview process.
Python Developer Skills
It is essential that when designing Python interview questions, you assess the technical skills, problem-solving abilities, and communication skills of a potential candidate. Below is a list of key skills and qualifications you should look for in potential candidates:
Python Developer Technical Skills
- Working knowledge of web development frameworks such as Django and Flask.
- Understanding of server-side templating languages such as Jinja2, Mako, and Cheetah.
- Knowledge of object-oriented programming (OOP) concepts such as classes, inheritance, encapsulation, and abstraction.
- Familiarity with databases such as MySQL, PostgreSQL, and MongoDB.
Python Developer Soft Skills
- Problem-solving abilities and analytical thinking
- Ability to work independently and manage multiple tasks
- Excellent communication skills
- Attention to detail
Python Developer Educational Qualifications
According to Western Governors University, the educational qualifications of a Python developer may vary depending on the position you are trying to fill.
- Generally, a Bachelor’s degree in computer science, software engineering, or related fields is sufficient, but if you are hiring for senior positions, the candidate may need a Master’s Degree or an advanced degree.
- Certification in Python programming, such as Certified Entry-Level Python Programmer (PCEP), Certified Associate in Python Programming (PCAP), Certified Professional in Python Programming 1 (PCPP-32-1), and Certified Professional in Python Programming 2 (PCPP-32-2).
Python Interview Questions
Below are some Python interview questions and sample answers that you can use to assess Python app development.
- Do you have any experience in software development with Python?
Sample answer: Yes, I have experience in software development with Python. In my most recent role as a software engineer at ABC Company, I was responsible for developing mobile applications with Python. I worked on a project where we used the Kivy framework to create an iOS and Android application for a client. I was responsible for coding the app, debugging, and optimizing the codebase.
- What have you done to optimize a software application in Python?
The candidate should mention techniques they have used to optimize the software application such as data caching, database indexing, and code refactoring.
Sample answer: I have used various techniques to optimize software applications in Python such as refactoring code using caching and profiling. For instance, I have used the cProfile module to profile Python code and identify areas of improvement. I have also used the Memcached library for caching data to improve application performance.
Python Web Developer Interview Questions
Below are Python web development interview questions that you can use to evaluate the knowledge and skills of a potential Python web developer.
- Can you describe the process of using Python to develop websites?
Sample answer: I would divide the process of developing Python websites into four parts:
- Designing the web page layout using HTML and CSS.
- Developing the back-end components using Python.
- Connecting the back-end to the front-end via a web framework such as Django or Flask.
- Testing and debugging the website.
- What are some Python frameworks you have used for web development?
Sample answer: I have experience with various web development frameworks including Django, Flask, and Pyramid. I have used Django to develop complex websites with multiple pages, user authentication, and database integration. I have used Flask for creating REST APIs and Pyramid for creating single-page web applications.
- What challenges have you faced while developing web applications with Python?
Sample answer: Some challenges I have faced while developing web applications with Python include debugging and performance optimization. Debugging can be difficult when you have multiple components interacting with each other. So, I use logging to keep track of the application's activities. I also use caching and data indexing techniques to improve the performance of the application.
Python Data Scientist Interview Questions
Below are Python interview questions for Data Science that you can use to assess the problem-solving and analytical capabilities of a potential Python Data Scientist.
- Which built-in data types does Python support?
Sample answer: Python supports several built-in data types including int (integer), float (floating-point number), list, tuple, set, and dictionary. An integer is a whole number that can be either positive or negative. A floating-point number is a decimal number, often used to represent decimal fractions. A list is an ordered collection of values that can be accessed with an index. A tuple is an immutable list and cannot be changed once created. A set is an unordered collection of unique values, and a dictionary is a collection of key-value pairs.
- What is the purpose of a Python class?
This is one of the most common Python data engineer interview questions. The candidate should explain the purpose of a Python class and how they can use it to create objects.
Sample answer: A Python class is a blueprint for creating objects. It is a group of related attributes and methods that one can use to create instances of the class. Classes are useful for organizing data and functions in a way that makes them easier to use and reuse. For instance, we can create a class to represent different types of cars, which would include the attributes such as make, model, and color, and methods such as accelerating and braking.
- How do you visualize data in Python?
Sample answer: Python has several libraries that data scientists can use for visualizing data such as Matplotlib, Seaborn, and Bokeh. Matplotlib is the most widely used library for creating static charts and graphs. Seaborn is a data visualization library based on matplotlib that provides a high-level interface for drawing attractive statistical graphics. Bokeh is an interactive visualization library that supports modern web browsers to create interactive plots, dashboards, and data applications.
- What is the difference between a series and a dataframe in Pandas?
This is one of the most important Python Pandas interview questions used to test the candidate’s knowledge of the Pandas library.
Sample answer: A series is a one-dimensional labeled array that can hold any data type such as integers, strings, floats, and Python objects. A dataframe is a two-dimensional data structure that consists of rows and columns. A dataframe can contain multiple series, which come organized into columns. It also provides methods for manipulating and analyzing data such as sorting, filtering, and grouping.
Python Advanced Interview Questions
The following advanced Python interview questions and answers are for experienced developers with extensive knowledge in the field.
- What is a decorator in Python?
Sample answer: A decorator is a function that takes another function as an argument and returns a modified version of the original function. Decorators make code easier to read, faster to execute, and more flexible. Developers can use them to modify existing functions without having to change the code itself.
- What is closure in Python?
Sample answer: A closure is a function that remembers the values of variables defined outside its scope. It allows you to create functions that have access to variables outside their scope, even after the original function has finished executing. Closures are often used in code optimization and higher-order programming.
- What is the purpose of regular expressions in Python?
Sample answer: Regular expressions match patterns in text. Developers can use them for various tasks such as validating input, searching and replacing data in strings, and extracting values from strings. Python has a built-in module called RE, which provides several functions for working with regular expressions.
Hire Python Developers
The interview process, though time-consuming, is an important part of the hiring process. Asking the right Python interview questions will help you find and hire a great Python developer with the right technical skills, problem-solving capabilities, and communication skills necessary to succeed in their role.
At Revelo, we understand the importance of finding the right Python developer for your team. That’s why we have developed a unique and comprehensive talent marketplace that matches companies with pre-vetted software engineers. Our platform helps you find the perfect Python developer in no time. Get in touch with us today and find your perfect tech hire!