Top Python Interview Questions with Answers

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python-interview-questions

 

Python is a widely used general-purpose, object-oriented, high-level programming language. It emerged as one of most popular coding languages in 2015, according to a survey by CodeEval.com. The popularity of the language is due to its versatility. In the recent years, the job opportunities for Python professionals have increased and if you are someone who is looking to start a career in a Python profile, you need to be well prepared.

 

Here are some of the commonly-asked Python interview questions and answers to help you in your next Python interview:

 

Q1. Is Python a case-sensitive programming language?

 

Ans. Yes, it is a case-sensitive language.

Q2. Name some of the features of Python?

 

Ans. Some features of Python are:

  • Supports functional and structured programming methods
  • It is very easy to learn
  • It supports automatic garbage collection
  • It can be easily integrated with C, C++, COM, ActiveX, CORBA, and Java

Q3. Is Python an Interpreted or Compiled language?

 

Ans. Python is an interpreted language. It converts the source code that is written by the programmer into an intermediate language, which is again translated into machine language before getting executed.

Q4. Name the supported data types in Python?

 

Ans. There are 5 standard data types in Python — numbers, strings, list, tuple and dictionary

Q5. Define “Pickling” and “Unpickling”

 

Ans. “Pickling” is the process whereby a Python object hierarchy is converted into a byte stream, and “unpickling” is the inverse operation, whereby a byte stream is converted back into an object hierarchy.

Q6. What is a dictionary in Python?

 

Ans. A dictionary is an associative array (also known as hashes) and are like a built-in mapping type.

 

 

Q7. Briefly explain the process of managing memory in Python.

 

Ans. Memory management in Python involves a private heap containing all Python objects and data structures. It also has an inbuilt garbage collector that recycles all the unused memory, frees it up, and makes it available to the heap space.

Q8. What is the difference between a tuple and a list?

 

Ans. The basic difference between a tuple and a list is that the former is immutable and the latter is mutable.

Q9. Are arguments passed by value or reference in Python?

 

Ans. In Python, arguments are always passed by value

Also Read>>Top Reasons to Learn Python and Hadoop

 

Q10. What is Web Scraping? How do you achieve it in Python?

 

Ans. Web Scrapping is a way of extracting the large amounts of information which is available on the web sites and saving it onto the local machine or onto the database tables. Python has few modules for scraping the web like urllib2, scrapy, pyquery, BeautifulSoap, etc.

Q11. How do you copy an object in Python?

 

Ans. Using the functions copy.copy() and copy.deepcopy()

Q12. Name a few libraries in Python used for Data Analysis and Scientific computations.

 

Ans. Some of the libraries used for data analysis and scientific computations are NumPy, SciPy, Pandas, SciKit, Matplotlib, Seaborn

 

 

Q13. Why one should use NumPy arrays instead of nested Python lists?

 

Ans. NumPy’s arrays are more compact than Python lists — a list of lists as you describe, in Python, would take at least 20 MB or so, while a NumPy 3D array with single-precision floats in the cells would fit in 4 MB.

Q14. What is a Python decorator?

 

Ans. A Python decorator is a specific change to the Python syntax that allows us to more conveniently alter functions and methods.

 

Also Read>>The Best Way to Learn Python

 

Q15. What is monkey patching? How can you do it in Python?

 

Ans. Monkey patching is making changes to a module or class while the program is running. A Monkey Patch in Python is a piece of code which extends or modifies other code at runtime (typically at startup).

Q16. What is a unittest in Python?

 

Ans. The unit testing framework of Python is known as unittest.

Q17. What is a negative index in Python?

 

Ans. Python sequences can be indexed as positive and negative numbers. A negative index accesses elements from the end of the list counting backwards.

 

Also Read>>5 Reasons to Learn Python!

 

Q18. What is the difference between Xrange() and range()?

 

Ans. Range() returns a list and xrange() returns an xrange object, which is kind of like an iterator and generates the numbers on demand.

Q19. Define module and package

 

Ans. A module is a Python object with arbitrarily named attributes that you can bind and reference.

A Python package is simply a directory of Python module(s).

Q20. Define “lambda” in Python.

 

Ans. It is a single expression anonymous function often used as an inline function.

These are some of the popular questions that are asked in a Python interview. Always be prepared to answer all types of questions — technical skills, interpersonal, leadership or algorithms. If you are someone who has recently started your career in Python, you can always get certified to have a good grasp on the programming language.

Along with these Python interview questions, some other Python interview questions that might come your way include –

Q21. Why lambda forms don’t have statements?

 
Ans. It is because a lambda form is used to make new function object and then return at runtime. Also, the syntactic framework of Python is unable to handle statements nested inside expressions.

 

Q22. What is Flask?

 
Ans. Flask (source code) is a Python micro web framework and it does not require particular tools or libraries.

Q23. How will you perform static analysis in a python application or find bugs?

 
Ans. PyChecker can be helpful as a static analyzer to identify the bugs in Python project. This also helps to find out the complexity related bugs. Pylint is another tool that is helpful in checking if Python module is at par with the coding standards.

Q24.When will you use the Python Decorator?

 
Ans. Python Decorator is used to quickly adjust the functions in Python syntax.

Q25.Can you tell me the generator functions in Python?

 
Ans. Generator functions help to declare a function that behaves like an iterator in a fast, easy, and neat way.

Q26. Python strings are immutable or mutable?

 
This is among the very commonly asked Python interview questions. Your reply should be –

Ans. Python strings are immutable. Ironically, it is not a string, but a variable with a string value.

Q27. What is PEP 8?

 
Ans. PEP 8 is the style guide of Python. It suggests the ways of formatting the Python code for maximizing its readability.

Q28. What is pass in Python?

 
Ans. Pass stands for no-operation Python statement. It means that pass is a null operation, nothing happens when it is executed.

You might come across some confusing Python interview questions, MCQ is one of the them, but do not get stumped. You should be thorough with your study and be well prepared for the Python interview questions.

Q29. Now, choose the right answer –

When “else” in try-except-else is executed?

  1. In case of any exception
  2. When no exception is there
  3. When an exception occurs in the except block
  4. Always

Ans. c) when no exception occurs

Q30. What is slicing?

 
Ans. Slicing is a computationally fast way to methodically access a range of items from sequence types like list, tuple, strings, etc.

Q31. How a list is reversed?

 
Ans. To reverse lists – list.reverse().

Q32. How a last object from a list is removed?

 
Ans. list.pop(obj=list[-1]) − Removes and returns last object from the list.

Q33. What is docstring?

 
Ans. Python documentation strings (docstrings) provide an easy way to document Python functions, modules and classes.

Q34. How to delete a file?

 
Ans. We can delete a file in Python by using a command os.remove (filename) or os.unlink(filename).

Q35. Is python a case sensitive language?

 
Ans. Yes, it is a case sensitive language like most of the widely used programming languages such as Java, C, C++, etc.

Q35. How many kinds of sequences does Python support? Name them.

Ans. Python supports seven sequence types –

  • Str
  • List
  • Tuple
  • Unicode
  • byte array
  • xrange
  • buffer

Q36. How will you reload a Python module?

 
Ans. reload() is used to reload a previously imported module.

Q37. What is a set?

 
Ans. A set is an unordered collection of iterable and mutable data, and it has no duplicate elements.

Q38. Name some standard Python errors.

 
Ans. Some standard errors in Python are –

  • TypeError
  • ValueError
  • NameError
  • IOError
  • IndexError
  • KeyError

We can use dir(__builtin__) to list all the errors in Python.

Q39. What is Tkinter?

 
Ans. Tkinter is the de-facto standard GUI (Graphical User Interface) package of Python.

Q40. What is multithreading?

 
Ans. Multithreading stands for running a number of programs simultaneously by invoking multiple threads.

These are some of the popular Python interview questions that are asked in a Python interview. Always be prepared to answer all types of questions — technical skills, interpersonal, leadership or algorithms. If you are someone who has recently started your career in Python, you should always take up Python certification and have a good grasp on the programming language, and perform well with Python interview questions.


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About the Author

Hasibuddin Ahmed

Hasibuddin Ahmed

Hasib is a professional writer associated with learning.naukri.com. He has written a number of articles related to technology, marketing, and career on various blogs and websites. As an amateur career guru, he often imparts nuggets of knowledge related to leadership and motivation. He is also an avid reader and passionate about the beautiful game of football.

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