Every day, more and more companies are searching for qualified programmers, web developers, and coders. Being fluent in a programming language can guarantee you a hefty salary and a great job position. Out of the thousands of programming languages that are currently out there, Python has shown itself to be on the most in-demand programming languages list. That’s why today we’ll talk about Python interview questions - to get you ready for that dream job interview!
In this tutorial, we’ll cover both the basic and technical sides of the interview. We shall start from the beginner (entry) questions, and build up to the more advanced ones as we progress through the tutorial.
Table of Contents
- 1. Getting to Know Python Basics
- 1.1. Question 1: What is Python?
- 1.2. Question 2: Can you name the type of Python language? Is it scripting or programming?
- 1.3. Question 3: What key features of Python could you name?
- 1.4. Question 4: Why is Python better than Java?
- 1.5. Question 5: How many data types are there in Python?
- 1.6. Question 6: What’s the difference between a ‘tuple’ and a ‘list’?
- 1.7. Question 7: What’s ‘pickling’ and ‘unpickling’?
- 1.8. Question 8: What is ‘lambda’?
- 1.9. Question 9: How is memory managed within Python?
- 1.10. Question 10: What is ‘pass’?
- 1.11. Question 11: Can you copy an object in Python?
- 1.12. Question 12: How to delete a file within Python?
- 1.13. Question 13: What is a ‘dictionary’?
- 1.14. Question 14: Is Python an interpreted language?
- 1.15. Question 15: Which of these is wrong?
- 1.16. Question 16: How is Python object-oriented?
- 1.17. Question 17: What is ‘slicing’?
- 1.18. Question 18: What is ‘namespace’ in Python?
- 1.19. Question 19: What is ‘self’ in Python?
- 1.20. Question 20: Do you really need to use ‘indentation’ in Python?
- 2. Advanced Python Questions
- 2.1. Question 1: Write a code that would calculate a list of given numbers.
- 2.2. Question 2: Write a code that would randomize items from the list.
- 2.3. Question 3: Is there a difference between ‘range’ and ‘xrange’?
- 2.4. Question 4: What is a Dogpile effect?
- 2.5. Question 5: Explain what is Encapsulation.
- 2.6. Question 6: When does Abnormal Termination happen?
- 2.7. Question 7: Write a code that would count all of the capital letters in your file.
- 2.8. Question 8: Does Python have a compiler?
- 2.9. Question 9: What is Monkey Patching?
- 2.10. Question 10: How to save an image when you know the URL?
- 2.11. Question 11: If list1 is [4, 6, 8, 1, 0, 3], what will list1[-1] be?
- 2.12. Question 12: What is a ‘decorator’?
- 2.13. Question 13: What are the 'sub()', 'subn()' and 'split()' methods?
- 2.14. Question 14: What do the processes of 'compiling' and 'linking' do?
- 2.15. Question 15: What do the functions ‘help()’ and ‘dir()’ do?
- 3. General Tips
- 4. Conclusions
Getting to Know Python Basics
Let’s take it from the top and start by covering the more general questions and answers. These are questions that you are most likely to get asked at the beginning of the interview, just to see if you truly do have a fundamental understanding of Python. After that, we'll move on to some technical questions and finish off with a few general tips and advice.
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Question 1: What is Python?
As you’ve probably expected, this is one of the very first Python interview questions that you’re bound to get asked. Your employers are probably going to expect a concise and thorough answer, so let’s provide them one.
Python is a portable, high-level programming language that has inbuilt automatic memory management, threads, strings, is object-based. It is loved for the simplicity and built-in data structure - the fact that Python is open source also contributes to its fame.
Question 2: Can you name the type of Python language? Is it scripting or programming?
Python is a general-purpose programming language that is capable, if needed, of scripting.
Question 3: What key features of Python could you name?
Before Python interview questions, take a look at the list of key Python programming language features:
- Python is one of the most universal programming languages. It can be interpreted, which means, that it does not need to be compiled before it is run.
- The programming language is dynamically typed. It does not require the user to state the variables before compiling. For example, you can write “x=123” or x="good" afternoon” without an error.
- Python is well suited to object-orientated programming. That allows the definition of classes along with composition and inheritance.
- Its’ functions are first-class objects. It can be assigned to variables, returned and passed into other functions.
- The use of Python is very wide - it can be used in automation, web applications, scientific modeling, big data applications, etc. It can be used as a combining element to get other languages and components to work together.
Question 4: Why is Python better than Java?
Some of your interview questions might involve comparisons with other programming languages - these can be random, but Java seems like the most common one that employers ask.
In short, Python (when compared with Java) is easier to use and has much better coding speeds. Also, when it comes to data, Java is statically typed, while Python offers dynamic typing. This is considered to be a huge advancement. But just to be sure, prepare for Python interview questions and answers.
Question 5: How many data types are there in Python?
One of the more common interview questions on Python - you might get asked to either say the number or name them.
Python has five different data types: string, list, number, dictionary, and tuple.
Question 6: What’s the difference between a ‘tuple’ and a ‘list’?
The main difference is that lists are slower, but they can be edited, while tuples work faster, but cannot be modified.
Question 7: What’s ‘pickling’ and ‘unpickling’?
Pickling happens when a module within Python is accepted and converted into a string module, and then later dumped into the file.
As opposed to that, unpickling is when you retrieve the string module from the file.
For such comparison-based Python interview questions, try to keep your explanations as simple as possible. Your potential employers will probably appreciate that you can explain tough topics in a simple-to-understand manner.
Question 8: What is ‘lambda’?
Lambda is an anonymously performed function with just one, single expression.
Question 9: How is memory managed within Python?
Python's private heap space is responsible for memory management. It is only accessible by an interpreter - if you’re a Python programmer, you won’t be able to reach it. The language also has an inbuilt recycler that is responsible for creating more free heap space (this is done by recycling unused memory).
Question 10: What is ‘pass’?
Pass simply indicates a space that should be left blank within the compound statement.
Question 11: Can you copy an object in Python?
Even though it sounds like one of the basic Python interview questions, you would probably be surprised how many people manage to stumble with it.
Yes, you can copy objects in Python, but not all of them. The most general and well-known way to do it is to use the
Question 12: How to delete a file within Python?
To delete something in Python, use the command os.remove(name_of_the_file).
Question 13: What is a ‘dictionary’?
Remember the data types that we’ve talked about earlier? The inbuilt ones? A dictionary is exactly that.
Dictionaries are comprised of keys and the key corresponding values. Here’s an example:
Question 14: Is Python an interpreted language?
Again, one of the most commonly asked Python interview questions - you should keep this in mind.
Yes, Python is an interpreted programming language. What does this mean? It’s a three-way process - you write source code, Python converts it into an intermediate language (for easier understanding) and then it’s yet again changed into machine codes that are then executed.
Question 15: Which of these is wrong?
a) xyz = 5,000,000
b) x,y,z = 1000, 3000, 7000
c) x y z = 1000 3000 7000
d) x_y_z = 5,000,000
The answer: C is the wrong one.
Question 16: How is Python object-oriented?
Object-oriented programming languages (OOPs) are based on classes and objects of those classes. Python is exactly that.
More so, Python possesses the features that are credited to OOPs - inheritance, polymorphism, etc.
Question 17: What is ‘slicing’?
In Python, slicing is when you select multiple items from places like lists, strings and so on.
So - those are the more basic Python interview questions that you might receive during your job interview. Now, let’s try and move more towards the advanced stuff and some untouched Python technical interview questions.
Question 18: What is ‘namespace’ in Python?
It is the process of naming the system that is used to make sure that all the names are unique and different.
Question 19: What is ‘self’ in Python?
Self is an instance or an object of a class. In Python programming language, it helps to differentiate between the methods and attributes of a class with local variables.
Question 20: Do you really need to use ‘indentation’ in Python?
Yes, it is crucial. Indentation specifies the block of code. Within the indented block, there are all the codes with loops, classes, and functions. If the code is not indented, it will not execute accurately and will show an error.
Advanced Python Questions
While the basic Python interview questions can be vital during the job interview, it is also important to pay some attention to the advanced ones, since most of the time they are more tricky to remember and learn.
Question 1: Write a code that would calculate a list of given numbers.
if len(num_List) == 1:
return num_List + list_sum(num_List[1:])
print(list_sum([3, 5, 8, 9, 9]))
Question 2: Write a code that would randomize items from the list.
from random import shuffle
x = ['Skyrim', 'Belongs', 'To', 'The', 'Nords']
[‘Nords’, ‘Skyrim’, ‘To’, ‘Belongs’, ‘The’].
Question 3: Is there a difference between ‘range’ and ‘xrange’?
Yes, albeit it might not be noticeable at first. In terms of functionality and the tasks they perform, both commands are nearly identical.
The key difference, however, is that
range (when used) brings back a list object, while
xrange returns an xrange object.
Question 4: What is a Dogpile effect?
This is one of the Python interview questions that might be tricky to memorize at first, so do give it a few good tries.
A Dogpile effect happens when a website’s cache expires, yet it is hit by many different requests from the user. This can cause many different problems, from lag spikes to complete crashes.
A system called semaphore lock is used to prevent Dogpiles from happening.
Question 5: Explain what is Encapsulation.
Encapsulation is one of the features that Python has because it’s an object-oriented programming language. Be sure to add this to your answer pool.
Encapsulation is a process of grouping related data members into one, single place. Along with the member, encapsulation also returns their functions, too.
Question 6: When does Abnormal Termination happen?
First of all, during the Python interview questions and answers, it should be said - abnormal termination is bad. You don’t want it to happen in your coding experience, although it’s almost unavoidable at one point or another, especially when you're a beginner programmer.
Abnormal termination is a crash of your program in the middle of its execution, while the main tasks are still running. This is usually caused by a faulty code or some software issues.
Question 7: Write a code that would count all of the capital letters in your file.
with open(I_LIKE_APPLES) as fh:
count = 0
text = fh.read()
for character in text:
count += 1
Question 8: Does Python have a compiler?
This is one of the tougher Python interview questions, mostly because not many people pay attention to it.
Python indeed does have its compiler, but it’s rather easy to miss. This is because it works automatically - you don’t notice it.
Question 9: What is Monkey Patching?
Monkey patching refers to modifications that you would make to the code when it’s already running.
Question 10: How to save an image when you know the URL?
To save an image locally, you would use this type of code:
Question 11: If list1 is [4, 6, 8, 1, 0, 3], what will list1[-1] be?
“-1” always points to the last index in a list, so the answer would be 3.
Question 12: What is a ‘decorator’?
There are a lot of terms that you need to know during Python interview questions and this is one of them. Decorators are used to inserting new and fresh pieces of code into an already existing class or function. With the help of decorators, you can make these codes run before or after the original one.
Question 13: What are the 'sub()', 'subn()' and 'split()' methods?
A module called “re” lets you modify your strings in Python. There are three methods of how you can do this:
- sub(): finds specific strings and replaces them.
- subn(): same as the sub(), but also return the new strings with the exact number of replacements.
- split(): splits a specific string into a list.
I’ve given you a very general overview of the three “re” methods of string modifications within Python. It is advisable to do more research on this topic before your job interview - these strings are usually a part of very popular Python interview questions that potential employers ask their job nominees.
Question 14: What do the processes of 'compiling' and 'linking' do?
I’ve already mentioned the Python compiler earlier, but this is also one of the questions and answers that you might find useful.
Compiling lets you, well… Compile new extensions within your code without any errors. After that, linking can be a fluid process - a successful compilation smoothens out linking and eliminates any possible issues throughout the process.
This can be considered one of the more easier Python coding interview questions if your potential employer doesn’t ask you to go in-depth.
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- Nanodegree Program
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Question 15: What do the functions ‘help()’ and ‘dir()’ do?
I thought it would be a good idea to finish off with one of the more Python technical interview questions.
Both of these functions can be accessed from the Python interpreter. They are used to view consolidated dumps from inbuilt functions.
help() shows you the documentation string, while
dir() displays the defined symbols.
Now that I’ve given you some of the more advanced Python interview questions, let’s move on to some general tips that you could apply before and during your interview.
Job interviews can be tough and stressful, but you shouldn’t let that get the better of you. You can read all of the questions and answers that you’ll find on the internet and still flunk that interview. How so?
First of all, your potential employer isn’t only going to ask you about Python. He might ask you about your previous experiences, check what kind of a person you are, get to know your hobbies - all of these factors are very important for landing that job.
One good way to leave a good impression is to not act like your life depends on the outcome of the interview - if you’re sitting there and trying to answer technical Python interview questions while sweating profusely and shaking like a leaf, you might scare the person your talking to.
Also, don’t be cocky - sure, you might have 20 years of expert Python experience, but what good will that do you if you don’t get the job only because you scoffed at some of the easier Python coding interview questions and came off as arrogant because of it?
Get a good night’s sleep and don’t worry about it - show your potential employer the person that you truly are, and you'll be likely to succeed. Remember - these people are professionals that deal with wannabe employees daily - if you try to lie or cheat, they will most likely catch on to you in mere seconds.
With such an increased need for Python programmers and developers, it wouldn’t be surprising if you went through hundreds of interviews with thousands of Python interview questions until you finally land that dream job - which can be a good thing! When you answer so many Python-related questions, you’ll become more and more relaxed and confident in your ability to succeed.
If you think that your Python skills are not up to the level for these questions, be sure to enroll in BitDegree's interactive Python tutorial to advance your skills.