Top 30 Python Interview Questions & Answers in 2020

Python is a highly standardized programming phrasing with dynamic semantics. Its top-level worked in information structures, in conjunction with dynamic formulating and dynamic authoritative; allow it to be exceptionally appealing for Quick Application Advancement. The two major reasons for using Python course is the quality of the output and developer productivity. With Courseinn candidates easily crack Python interview questions & answers, with our professional training, we guarantee 100% satisfaction for your investment and plus Python Certification will help you further to boost your career.

For easy understanding & crack interview, here we have compiled all the top Python interview questions from different categories such as

1. Basic Interview Questions
2. OOPS Interview Questions
3. Basic Python Programs
4. Python Libraries Interview Questions
5. Web Scraping Interview Questions
6. Data Analysis Interview Questions
7. Multiple Choice Questions (MCQ)

Top 30 Python Interview Questions & Answers

Question 1. What is Python?

Python is an object-oriented and high-end programming language which is primarily used for web and app development.  It was developed by Guido van Rossum, and it is released in 1991. It is used for server-side web development, system scripting, mathematics, and Application development.

Question 2. What are the benefits of using Python?

Some of the advantages of using Python programming language are 

• It has extensive support libraries.
• It has an excellent integration feature. With Python, it is easy to develop web services through invoking COBRA and COM components.
• Through the strong integration features, the unit testing framework and enhanced control capabilities, it enhances the speed for many applications.
• The Python language comprises of extensive programmers productivity through its support libraries and object-oriented designs.

Question 3. What do you understand PEP8?

PEP8 is Python Enhancement Proposals which a tool to verify your python code against some of the style conventions. It also provides a reference point for the Pythonic way to write code.

Question 4. What type of language is Python? Programming or scripting?

Python is considered a scripting language due to its historic blur between scripting languages and general-purpose programming languages. In fact, Python is not a pure scripting language, but a general-purpose programming language that also works as well as a scripting language.

Question 5. What are the key features of Python?

It has an easy to use a syntax

• Python is easy to write programming language
• Python comes with a large standard library which supports many common programming tasks such as connecting to web servers, searching text with regular expressions, reading and modifying files.
• It is easy to test short snippet of code.
• Its free software.
• It can run on all platforms

Question 6. How is Python an interpreted language?

An interpreted language is whichever programming language that isn’t already implemented in “machine code” prior to runtime. So, Python will be under byte code interpreted. The .py source code is initially compiled to byte code as .pyc. This byte code can be interpreted (CPython), or JIT-compiled (PyPy). Python(Cpython) is neither a true compiled time nor a purely interpreted language but it is called interpreted language.

Question 7. What is the difference between list and tuple in Python?

The list is mutable while tuple is not mutable in Python which is the major difference. Tuple can be hashed for e.g as a key for dictionaries.

Question 8. How would you convert a string into an int in Python?

When a string contains only numerical characters, you can easily convert it into an integer using the int() function.

For example,

int('235')
235
Let’s check the types:
type('235')

type(int('235’))

Question 9. Define modules in Python:

The module is defined as a file that consists of a set of various functions and Python statements which we want to add in our application. 

Example of creating a module:
To create a module first, we need to save the code which we want in a file with a .py extension. save the module with module.py

def wishes(name):
Print("Hi, " + name)

Question 10. What is pickling and unpickling?

The Pickle module accepts whatever Python object and converts it into a string representation and put it into a file by using a dump function, this process is called pickling. While the process of recovering original Python objects from the stored string representation is called unpickling.

Question 11. What datatypes does python support?

Basically, Python supports 14 Data Types.

• int: It is used to symbolize integral values, Python2 had a datatype called long but from Python3 long can also be used and it is represented by int.
• float
• complex
• bool
• str
• bytes
• bytearray
• range
• list
• tuple
• set
• frozenset
• dictionary
• None

Question 12. What is the statement that can be used in Python if the program requires no action but requires syntactically?

The pass statement is a null operation in Python. When it is executed, nothing will happen. You should always use “pass” keyword in lower case. For example,

letter = "Hi Hello!"
for i in letter:
if i == "H":
pass
print("Letter Found:", i)
else:
pass

Question 13. Name the built in types available in Python:

 The built-in types in Python are as follows:

• Integer
• Complex numbers
• Floating-point numbers
• Strings
• Built-in functions

Question 14. What is for-else and while-else in Python?

For-else loops :

For loops also have an else clause. The else clause executes after the loop. This means that the loop did not encounter a break statement.

for item in container:
            if search_something(item):
               # Found it!
               process(item)
               break
        else:
            # Didn't find anything..
            not_found_in_container()

While-else loops :

The else block is executed only if while condition is false

Example:

while condition1:
if condition2:
break
else:
print('I am here because condition1 is False')

Question 15. What is the purpose of PYTHONSTARTUP, PYTHONCASEOK, and PYTHONHOME environment variables?

PYTHONSTARTUP

It includes the path of an initialization file containing Python source code. It will be executed every time you start the interpreter. It is called as .python rc.py in Unix and it holds commands that load utilities or modify PYTHON PATH

PYTHONCASEOK

It is used in Windows OS to instruct Python to find the first case-insensitive match in an import statement. Set this variable to any value to activate it.

PYTHONHOME

 It is an alternative module search path. It is generally embedded in the PYTHONSTARTUP or PYTHON PATH directories to compose switching module libraries easy.

Question 16. Mention what are the rules for local and global variables in Python?

Local variables:

When a variable is assigned a new value anyplace within the function’s body, it’s implicit to be local.

Global variables:

The variables that are referenced only inside a function are absolutely global.

Question 17. How do you remove the leading whitespace in a string?

strip() Python String strip() function in Python will remove leading and trailing whitespaces. If you like to remove only the leading or trailing spaces, you can use lstrip() or rstrip() function instead.

Question 18. What are the tools that help to find bugs or perform the static analysis?

PyChecker is a static analysis tool which detects the bugs in Python source code and it also warns the style and complexity of the bug. Pylint is another tool that checks whether the module meets the coding standard.

Question 19. What are Python decorators?

A Python decorator is an exact change which we make in Python syntax to alter functions easily.

Question 20. What is frozenset in Python?

 Frozensets are just like sets in Python but they cannot be changed. Clearly, frozensets are the immutable version of Python sets.

Question 21. What do you understand by the term namespace in Python?

A namespace in Python is defined as a system which is designed to provide a unique name for each object in python. Types of namespaces present in Python are as follows

• Local namespace
• Global namespace
• Built-in namespace

Question 22. Define the Scope of an object in Python:

Scope points to the availability and accessibility of an object in the coding region in Python.

Question 23. Mention what is the difference between Django, Pyramid, and Flask?

Flask is a “microframework” which was primarily built for a small application with very minimal requirements. In flask, you need to use external libraries. Flask is ready to use.

Pyramid is built for very larger applications. It gives flexibility and lets the developer use the right tools for their project. The developer can choose the database, URL structure, templating style, etc for the project. Pyramid is usually heavy configurable.

Like Pyramid, Django can also be used for larger applications. It comprises of an ORM.

Question 24. Mention what is Flask-WTF and what are their features?

Flask-WTF provides simple integration with WTForms. Features in Flask WTF are:

• Integration with wtforms
• Secure form with csrf token
• Global csrf protection
• Internationalization integration
• Recaptcha supporting
• File upload that works with Flask Uploads

Question 25. What is Python String format and Python String replace?

Python String Format:

The String format() method in Python is largely used to format the provided string into an accurate output or result.

Syntax for String format() method:

template.format(p0, p1, …, k0=v0, k1=v1, …)

Python String Replace:

This method is primarily used to return a copy of the string in which all the happening of the substring is replaced by another substring.

Syntax for String replace() method:

str.replace(old, new [, count])

Question 26. Name some of the built-in modules in Python?

The built-in modules in Python are as follows:

• sys module
• OS module
• random module
• collection module
• JSON
• Math module

Question 27. What is namespace in Python?

In Python, every name launched has a place where it resides and can be hooked for. This is defined as namespace. The namespace is like a box where a variable name is mapped to object placed. Each time the variable is searched out, this box will be searched, to obtain corresponding object.

Question 28. What are the functions in Python?

In Python, functions are defined as a block of code that is executable only when it is called. The def keyword is used to define a function in Python.

Example:

def Func():
print("Hello, Welcome to Courseinn")
Func(); #calling the function
Output: Hello, Welcome to Courseinn

Question 29. Explain lambda expressions. When would you use one?

If we want a function with a single expression, we can very well define it anonymously. A lambda expression might take input and returns a value. We type the following code in the interpreter to define the above function as a lambda expression.

 (lambda a,b:a if a>b else b)(3,3.5)

Question 30. What are the applications of Python?

Some of the applications of Python are:

• GUI based desktop applications
• Image processing applications
• Business and Enterprise applications
• Prototyping
• Web and web framework applications

Conclusion:

Python course is basically a really fun and rewarding language to discover and I think anyone can be able to get to a high level of capability in it. In the event that they find the right motivation. I hope this guide has been useful in your journey. If you have some other methods to suggest, please let us know! Find out more about how you can learn Python course, Python Certification and add this skill to your portfolio by visiting Dataquest.