Best Python Interview Questions And Answers

Interviews are stressful for everyone. Candidates are trying to present themselves as fitting for the job and great employees while hiring managers want to create a comfortable environment and find their perfect employee through a couple of basic Python interview questions. 

However, a little bit of preparation goes a long way for both parties. It will help Python developers reduce stress and do their best and hiring managers will know what Python advanced interview questions to ask to get the most accurate picture of the candidate. 

Here is the list of Python interview questions and answers that can help you prepare and go through the most successful and efficient interviews!

Junior Python Developer Interview Questions

01

What is Python mostly used for?

Python most often used a scripting language” for web applications as it does a great job automation specific services of tasks making it more efficient. This being said, Python is most often used for building software applications, shells of operating systems, pages within a web browser, and for some types of games. 

02

Is Python case-sensitive?

Yes, Python is a case-sensitive programming language meaning that Variable and variable have different values.

03

Is Python an interpreted language?

Yes, since it does not have machine-level code before runtime. Code uses an interpreter to be executed by the machine. 

04

What is slicing in Python?

Slicing is taking parts of strings, arrays, tuples, and lists. Its syntax is [start : stop : step].

05

How to delete a file from Python?

Import OR module and use os.remove(). 

06

What are built-in data types in Python?

  • non-type - has the null value
  • numeric types - integers (with booleans as sub-type), floating-point, and complex numbers
  • sequence types - lists, tuples, and range objects
  • mapping types - maps hashable values, the only type in Python is a dictionary
  • set types - set, frozenset
  • modules support a single operation - attribute access mymod.myobj
  • callable types - types to which a function can be applied

07

What is the difference between tuples and lists in Python?

Unlike lists, tuples are not editable and faster. They also have different syntax: 

for tuples: tup_1 = (10, ‘Chelsea’ , 20)

for lists: Syntax: list_1 = [10, ‘Chelsea’, 20]

08

What is the difference between pass by value and pass by reference?

Pass by value is the passing of the copy. If the copy is edited, the original object will remain the same. 

Pass by reference is passing of the reference to the original. Edits in the reference will result in changes in the original object. 

09

What are pickling and unpickling?

Pickling is the process of converting any Python object into a string representation. Unpickling is picking the object out of the string representation. 

Mid Python Developer Interview Questions

01

What will be the output of ['!!Python!!']*2?

['!!Python!! ', '!!Python!!']

02

What is PEP?

It is a Python Enhancement Proposal, guidelines that determine Python code formats for better readability.

03

What is the difference between arrays and lists in Python?

Arrays can store only one data type while lists store any data type. 

04

How to comment on multiple lines of code in Python?

In order to comment in Python, you need to put this character # in front of the comment. In order to comment on more than one line, you should press Ctrl and left-click all the lines that this comment is about. 

05

What are help() and dir() functions?

Help() function displays all the documentation and information about modules, attributes, and so on. Dir() function displays defined symbols. 

06

What are namespaces in Python?

A namespace is used for creating unique object names that will not cause a conflict later. Some namespaces are:

  • local namespace is temporarily created for a functional call and as soon as the call returns, it is cleared
  • global namespace contains names from modules and packages
  • built-in namespace includes names and functions of core Python 

07

What are decorators in Python?

Decorators add functionality to the current function without changing its structure. It can also accept arguments and modify these arguments.

08

How to use self in Python?

The keyword self defines an instance or object of a class and helps to differentiate between methods and attributes of a class.

09

How are .py and .pyc files different?

.py file includes the source code while .pyc includes the bytecode (intermediate between source code and machine-level code).

10

What is the use of with in Python?

With statement makes exception handling easier: encapsulates cleanup and preparation, assists in file stream management, and makes code more readable.

Senior Python Developer Interview Questions

01

What is monkey-patching?

Python developers are able to make dynamic edits, edits of the module during the runtime. Monkey-patching helps them do so.

02

What is type conversion in Python?

It is used for converting one data type into the other, for example, characters into an integer - ord(0), any data type to list type - list(), integer into a string - str(), etc.

03

What are the advantages of NumPy?

NumPy uses less storage, is faster, and has many vector and matrix operations that eliminate the need for oftentimes unnecessary work. Its slicing and broadcasting functionality are more powerful than those of regular Python lists.

04

How to achieve multithreading in Python?

Python offers a multi-threading package but it is not really good for speeding up the code. The GIL is a great way though it is not really multithreading. It executes one at a time but takes turns for different threads really fast which makes it seem like processes are running simultaneously. 

05

How to remove whitespace from a string?

Python offers a strip function that is already built-in. It clears all the whitespace or trailing spaces automatically. 

06

What is a negative index in Python?

-1 is the last negative index, while -2 is the second last and so on. It is mainly used to traverse the element backward. 

07

What are the three most popular libraries in Python? How do they differ?

Those are Django, Flask, and Pyramid. Flask aims at small applications while Django and Pyramid were created for larger projects. Pyramid is very flexible, developers can choose all the tools they want from database to templating style. Django has ORM and many other tools out of the box.

08

Is Python good for data analysis?

Python works great for data analysis especially for data mining, data processing and data visualization. Senior software developers should be able to answer all the Python data science interview questions in detail.

09

What are the pitfalls and problems of Python language?

The slow overall performance of Python, its limited multiprocessing and threading capabilities are considered to be the major pitfalls of this programming language.  

10

Does Python support multiple inheritance?

There are only a few modern programming languages supporting multiple inheritance and Python is one of them. So yes, it has the ability to derive a class from multiple base classes at the same time.

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