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Python Developer Interview

21 Questions and Answers by William Swansen
| William Swansen is an author, job search strategist and career advisor who assists individuals from all over the world.

Question 1 of 21

Explain a Python dictionary and what it is used for.

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Python Developer Interview Questions

  1. 1.

    Explain a Python dictionary and what it is used for.

      This is a technical question meant to determine your knowledge of the Python programming language. As the interview progresses, the technical questions will become more difficult and more complex. This indicates that the interviewer is gaining confidence in your abilities and is seeking to explore your background in more detail. Continue to answer the questions directly and briefly, and anticipate follow-up questions any time you provide an answer.

      William's Answer

      "A Python dictionary is a collection of data types. The dictionary defines the relationship between keys and values. Since the dictionary is indexed by keys, you can use these to identify the values."

  2. 2.

    What is Flask as it is used in Python, and what are some of its benefits?

      You should easily recognize this as a technical question since it asks about a specific feature of the Python programming language and requests that you describe some of its benefits. This fits the traditional format of a technical question because it requires you to define a term and then discuss its use. As with all technical questions, be sure to keep your answer brief and to the point and be prepared for a follow-up question.

      William's Answer

      "The purpose of Flask within Python is to map the URLs and web addresses used in browsers to specific functions within a python program. It is very similar to Django but requires additional coding to work properly. This feature makes it easier for coders and therefore Flask as more commonly used than Django."

  3. 3.

    What tools do you use to identify bugs in your code?

      When an interviewer asked you about how you identify bugs in your code, they seek to learn several different things. The first is your ability to troubleshoot issues when coding. Second, they want to understand the tools you use to perform this operation and whether they are the same ones used in their organization. Researching both the company and the job before the interview will help you respond to this question with the appropriate answer.

      William's Answer

      "The main tool I use to identify bugs in the code I write is PyChecker. This is pretty common in the industry, and I believe your software team uses the same tool. I like it because not only does it help identify the issue, but it also describes the complexity of the bug, which helps me to resolve it."

  4. 4.

    Can you give me an example of Inheritance and describe what it is used for?

      It is easy to identify this as a technical question since it asks you about a concept used in work performed by a Python developer and requests that you provide an example. Keep in mind that technical questions are best answered directly and briefly, with little embellishment. The interviewer will ask additional questions if they need more information.

      William's Answer

      "Inheritance describes Python’s ability to allow one class to gain all the attributes and methods of another. The benefit of this is that it makes code reusable, reducing the time it takes to develop an application. There are several types of inheritance in Python. These include single, multilevel, multiple, and hierarchical."

  5. 5.

    Can you describe the major features of the Python programming language?

      This is a general question which the interviewer will ask early in the interview to begin the conversation, learn more about your background, and collect information they can use throughout the interview. Your answer to this question will allow you to direct the interview towards a specific area or topic you are comfortable with.

      William's Answer

      "Pythion offers developers several advantages when writing code. First, like PHP and Ruby, Python does not have to be compiled before it is run. Also, Python is well suited to object-oriented programming and allows for the definition of classes, composition, and inheritance. Finally, Python allows for the inclusion of C-based extensions, which helps to avoid bottlenecks. This is important since Python typically runs slower than languages which are compiled."

  6. 6.

    What are some of the common modules that are part of Python?

      This technical question asks you about some of the features of the Python programming language. Throughout the interview, the hiring manager will ask you a variety of different technical questions. These will range from very basic to very complex. The best way to prepare for this, in addition to doing your research, is to practice questions like these out loud. This will make you comfortable responding to the questions during the interview.

      William's Answer

      "Python modules are files which contain code. The file is identified by .py and contains executable code, including functions, classes or variables. Some common modules are:
      data time"

  7. 7.

    Describe the differences between arrays and lists as Python uses them.

      When asked to compare two items during an interview, you should begin by first defining each item. This will confirm that you are answering the question the interviewer asked you. You then briefly describe the differences, as requested. If applicable, you can provide examples of each of the items to illustrate their differences. As with any technical question, keep your answers brief and to the point, and anticipate follow-up questions.

      William's Answer

      "Arrays and lists, as used in Python, have many similarities since they are both methods for storing data. The key difference is that arrays can only hold a single type of data elements, while lists can contain any data type. An example is that array can contain only numbers or text, while a list can contain both numbers and text."

  8. 8.

    What is your process for tracking versions of your code?

      This is an operational question. Operational questions help the interviewer understand how you go about doing your job. When answering operational questions, you should keep your answer brief and to the point. The interviewer will ask you a follow-up question if they need additional information.

      William's Answer

      "I have found that the easiest way for tracking versions of my code is to use a process known as version control. Each time I update the code, I save it under a distinct file name that contains the version number and the date. This enables me to track the versions and to retrieve earlier versions if I need them."

  9. 9.

    Have you ever used Python to create a personal application?

      An interviewer will ask this type of question to gauge your interests in and proficiency with this programming language. While their primary interest is in your ability to perform the job for which they are interviewing you, knowing more about your interests and what you do outside of work will help them determine how well you will fit into their organization. Even if you have never created an application for your personal use, you should have an answer prepared for this question, demonstrating your interests in Python and improving your coding skills using this language.

      William's Answer

      "While not at work, I enjoy playing around with Python to explore features I don’t use in my job. I have used the programming language to create several websites for myself and my friends, and I’m currently working on a program to help me automate things around my house such as lights, sprinklers and appliances which have wifi connections."

  10. 10.

    What does the map function do in Python?

      Yet another technical question asking you about a specific function within the Python programming language. As a reminder, you should first define the function and then discuss what it does, providing examples if you feel it is necessary. Practicing this format for your answers can help you respond to any technical question asked by the interviewer.

      William's Answer

      " The map function executes the first argument of all the elements of a particular iterable. It can also manage multiple iterables if the function provides multiple arguments. The benefit of this was to enabled programmers to link the specific functions with specific iterables."

  11. 11.

    What is meant by Python supporting multiple instances of Inheritance?

      This is a follow-up to a previous question, 'Can you give me an example of Inheritance and describe what it is used for?'. Any time you provide an answer to an interviewer, you should anticipate follow-up questions. These indicate that the interviewer either needs additional information or has a specific interest in the topic. It also signals that you should focus more on this area, providing answers that encourage the interviewer to explore it in more detail. Your answers will help convince them that you are the right candidate for this position.

      William's Answer

      "Within the context of Python, multiple inheritances means that a class can be derived from more than one other class. These other classes are called parent classes. This was one of the features that differentiate Python from other programming languages such as Java."

  12. 12.

    How do you perform compiling and linking in Python?

      Since this question asks about how you perform specific processes, you can easily identify it as an operational question. Operational questions should be answered briefly and directly, with little embellishment. The interviewer will likely ask you a follow-up question to explore your processes in more detail. If it is applicable, you can break the process down into discrete steps and describe these sequentially to the interviewer.

      William's Answer

      "The process for compiling and linking in Python begins with creating a file and naming it using a convention that is supported by the compiler. The file should be stored in the modules directory. You then run the file using the command “spam file.o.” After the process is complete, you rebuild the interpreter using a make command. If the file has been updated, you then run the command ‘make Makefile’.’"

  13. 13.

    What are some of the common mistakes coders make when using Python?

      This is a general question that is meant to test your knowledge of and experience with coding In Python. The interviewer seeks to understand how knowledgeable you are with this programming language and whether you can identify common mistakes made while coding. The purpose of this latter point is to see if you are capable of rectifying the mistakes or avoiding them altogether. Answering this question properly will demonstrate your qualifications for this position, especially if you are interviewing for a senior programmer or manager's role.

      William's Answer

      "Probably the most common mistake I come across when reviewing other programmer’s code is that they use tabs instead of spaces in their programs. Other common issues include typing errors and problems with identifiers and variables. Most of these are easy to fix, and I use them as teaching opportunities when mentoring junior programmers."

  14. 14.

    Describe the differences between deep copy and shallow copy when writing code in Python.

      Technical questions like this one can be answered using a standard format. Since it asks you to compare two processes used in your job, you start by defining each process. You then compare the similarities and differences between them. Finally, you can provide examples if you feel this will strengthen your answer. Using a standard format likes this makes it easier to organize your thoughts and respond to an interviewer’s questions.

      William's Answer

      "Shallow copy is a technique used to create new instance types while maintaining the original ones. It copies both the reference pointers and the values of the original. Deep copy is used to store values that have already been copied. It does not copy the reference pointers. The key difference between these is that changes made with shallow copy will update all the instances, while those made with deep copy will not be affected if changes are made in the original copy. When executing a program, shallow copy was faster than deep copy."

  15. 15.

    Can you discuss Python lists and NumPy arrays, and why one is preferable to the other?

      This is an example of a technical question that asks you about two elements of the programming language you use and requests that you state a preference for one or the other. In most cases, your preference is neutral, as long as you can defend why you chose the particular item. However, if the interviewer or the organization has a strong preference for one of the items, it would be best if your stated preference matched theirs. The exception to this rule is if your preference would improve their operations, and you’re able to explain this in detail.

      William's Answer

      "Python’s lists are good general-purpose containers. They are easy to build and manage and support all of the data operations you need to perform. NumPy is more efficient and easier to use than lists. It provides you with many vector-matrix operations, which will eliminate some of the coding you need to do. NumPy is also faster and supports vectorized operations, which Python’s lists do not."

  16. 16.

    Please walk me through the steps of installing Python on Windows.

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  17. 17.

    Can you describe some of the type conversions used with writing code in Python?

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  18. 18.

    What are the differences between local and global variables in Python?

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  19. 19.

    How does Python manage memory?

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  20. 20.

    Why is Python described as an 'Interpreted' programming language?

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  21. 21.

    In your opinion, what are the benefits of writing code in Python?

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