200+ Python Developer Interview Questions and Answers

Testers focus on finding defects while developers focus on creating software.

• Testers are responsible for testing the software and finding defects.

• Developers are responsible for creating the software and fixing defects.

• Testers use test cases and scenarios to ensure the software meets requirements.

• Developers use programming languages and tools to create software.

• Testers work closely with developers to ensure defects are fixed.

• Developers work closely with testers to understand a...read more

Python has built-in data structures like lists, tuples, sets, and dictionaries.

• Lists are mutable and ordered, used for storing multiple items.

• Tuples are immutable and ordered, used for storing multiple items.

• Sets are mutable and unordered, used for storing unique values.

• Dictionaries are mutable and unordered, used for storing key-value pairs.

Decorators are functions that modify the behavior of other functions. Palindrome and prime number codes are also commonly asked in Python interviews.

• Decorators are denoted by '@' symbol and placed above the function definition

• They can be used to add functionality to a function without modifying its code

• Examples of decorators include @staticmethod, @classmethod, and @property

• Palindrome number code checks if a number is the same when read forwards and backwards

• Prime number code...read more

Lists are mutable while tuples are immutable.

• Lists are enclosed in square brackets [], while tuples are enclosed in parentheses ().

• Elements in a list can be added, removed or modified, while elements in a tuple cannot be modified.

• Lists are used for collections of homogeneous items, while tuples are used for collections of heterogeneous items.

• Lists are generally used for sequences that need to be modified frequently, while tuples are used for sequences that are accessed freque...read more

List and tuple are both sequence data types in Python. Lists are mutable while tuples are immutable.

• Lists are created using square brackets [] while tuples use parentheses ()

• Lists can be modified by adding, removing or changing elements while tuples cannot be modified

• List functions include append(), extend(), insert(), remove(), pop(), index(), count(), sort() and reverse()

• Tuple functions include index() and count()

• Lists are used when the data needs to be modified while tuple...read more

Python is a versatile programming language known for its simplicity and readability. It supports multiple programming paradigms and has a vast standard library.

• Python features include dynamic typing, automatic memory management, and support for multiple programming paradigms like procedural, object-oriented, and functional programming.

• Python is known for its readability and simplicity, making it a popular choice for beginners and experienced developers alike.

• Python has a vast...read more

Variables are containers for storing data. Loops are used to iterate over a sequence of elements. OOPs is a programming paradigm based on objects and classes.

• Variables are used to store data in memory. They can be assigned different values and data types.

• Rules for naming variables: must start with a letter or underscore, can contain letters, numbers, and underscores, cannot start with a number.

• Loops are used to execute a block of code repeatedly. Types of loops include for lo...read more

Use super() method to call parent's init method in child class.

• Use super() method in child class to call parent's init method.

• Pass the child class and self as arguments to super() method.

• Access the parent class attributes and methods using super().

self is a reference to the instance of the class and is used to access its attributes and methods.

• self is the first parameter of any method in a class.

• It is used to refer to the instance of the class within the class itself.

• self allows the instance to access its own attributes and methods.

• It is automatically passed when a method is called on an instance.

Lists are mutable in Python.

• Lists can be modified after creation, allowing for addition, removal, and modification of elements.

• Tuples, strings, integers, and floats are immutable in Python.

• Example: list_example = [1, 2, 3]; list_example[1] = 5 # modifies the list element at index 1 to 5.

The question covers libraries, APIs, and previous projects.

• Python has a vast collection of libraries for various purposes.

• API stands for Application Programming Interface and is used to interact with software applications.

• I have worked on projects involving web scraping, data analysis, and machine learning.

• In a previous project, I faced a challenge with data cleaning and had to use regular expressions to solve it.

Developed a sentiment analysis web app using Flask, NLTK and AWS

• Used Python to scrape Twitter data using Tweepy API

• Preprocessed data using NLTK library

• Trained a machine learning model using scikit-learn

• Deployed the app on AWS Elastic Beanstalk

• Implemented user authentication and authorization using Flask-Login

To import views in Django, you need to create a views.py file and import it in urls.py

• Create a views.py file in your Django app directory

• Define your views in the views.py file

• Import your views in urls.py using the 'from . import views' syntax

• Map your views to URLs in urls.py using the 'path()' function

Data structures are ways of organizing and storing data in a computer so that it can be accessed and used efficiently.

• Arrays - a collection of elements of the same data type

• Linked Lists - a collection of nodes that contain data and a reference to the next node

• Stacks - a collection of elements that follows the Last In First Out (LIFO) principle

• Queues - a collection of elements that follows the First In First Out (FIFO) principle

• Trees - a hierarchical data structure that consis...read more

Swap elements in pairs of two in a given list.

• Iterate through the list with a step of 2.

• Swap the current element with the next element.

• Continue until the end of the list or the last pair of elements.

Yes, we can change the order of a dictionary in Python.

• Use OrderedDict to maintain the order of insertion

• Sort the dictionary based on keys or values

• Convert the dictionary to a list of tuples and sort them

• Use the sorted() function to sort the dictionary

Lambda functions are anonymous functions that can be defined in a single line of code.

• Lambda functions are defined using the lambda keyword.

• They can take any number of arguments, but can only have one expression.

• They are often used as arguments for higher-order functions.

• Example: lambda x: x**2 defines a lambda function that squares its input.

Yes, I have experience working with various technology stacks.

• I have worked with Python, Django, Flask, React, Angular, and Node.js in my previous projects.

• I am comfortable adapting to new technologies and learning new stacks as needed.

• I have experience collaborating with cross-functional teams that use different technology stacks.

Python handles conditional statements using if, elif, and else keywords to control the flow of the program.

• Python uses if, elif, and else keywords to create conditional statements.

• Indentation is crucial in Python to determine the scope of the conditional statements.

• Example: if x > 5: print('x is greater than 5')

• Example: if x > 5: print('x is greater than 5') elif x == 5: print('x is equal to 5') else: print('x is less than 5')

Postman is a popular API development tool used for testing, documenting, and sharing APIs.

• Postman allows developers to send HTTP requests and receive responses from APIs

• It provides a user-friendly interface for creating and managing API requests

• Postman also offers features like automated testing, mock servers, and collaboration tools

• It supports various authentication methods and formats like JSON and XML

To build ourselves for technology needs, we need to constantly learn and adapt to new technologies and trends.

• Stay updated with the latest technologies and trends in the industry

• Attend conferences, workshops, and webinars to learn new skills

• Practice coding regularly and work on personal projects to improve skills

• Collaborate with other developers and participate in open source projects

• Read blogs, articles, and books related to technology

• Be open to learning new programming lang...read more

Find the sum of unique numbers in a list.

• Create an empty set to store unique numbers

• Loop through the list and add each number to the set

• Sum up the numbers in the set

I rate myself as an experienced Python developer with strong skills in various Python libraries and frameworks.

• I have worked on various Python projects and have a good understanding of the language syntax and concepts.

• I am proficient in using popular Python libraries such as NumPy, Pandas, and Matplotlib for data analysis and visualization.

• I have experience in developing web applications using Python frameworks such as Django and Flask.

• I am familiar with using Python for mach...read more

Python uses automatic memory management through garbage collection.

• Python uses reference counting to keep track of objects in memory.

• When an object's reference count reaches zero, it is deleted by the garbage collector.

• Python also uses a cyclic garbage collector to detect and delete circular references.

• Memory can be managed manually using the ctypes module.

• Python's memory management is efficient but can lead to performance issues with large datasets.

PEP stands for Python Enhancement Proposal. PEP8 is a style guide for Python code.

• PEP is a process for proposing and discussing new features and changes to Python.

• PEP8 is a style guide for Python code, covering topics such as naming conventions, indentation, and whitespace.

• PEP8 is not mandatory, but following it can make code more readable and consistent.

• Examples of PEP8 guidelines include using four spaces for indentation, using lowercase with underscores for variable names,...read more

Commonly used inbuilt functions of Python

• print() - prints output to console

• len() - returns length of an object

• range() - generates a sequence of numbers

• type() - returns type of an object

• str() - converts an object to string

• int() - converts a string or float to integer

• float() - converts a string or integer to float

• list() - creates a list

• dict() - creates a dictionary

• set() - creates a set

A global variable is a variable that can be accessed from any part of the program.

• Global variables are declared outside of any function or class.

• They can be accessed and modified from any part of the program.

• Using global variables can make the code harder to read and debug.

• Example: x = 10 (declared outside of any function or class)

Python code for multi threading

• Import the threading module

• Create a class that inherits from the Thread class

• Override the run() method in the class with the code to be executed in the thread

• Create instances of the class and start the threads using the start() method

Handling real-time errors in a web application

• Implementing proper error handling mechanisms such as try-except blocks

• Logging errors to track and troubleshoot issues

• Using monitoring tools like Sentry or New Relic to detect errors in real-time

Models in Django are Python classes that define the structure of the database tables.

• Models are used to create, read, update and delete data from the database.

• They define the fields and their types, relationships between tables, and constraints.

• Models can be created using the Django ORM (Object-Relational Mapping) or by writing SQL.

• Example: class Book(models.Model): title = models.CharField(max_length=100) author = models.ForeignKey(Author, on_delete=models.CASCADE)

• Models are...read more

Corestack is a cloud automation and orchestration platform that helps enterprises manage their cloud infrastructure.

• Corestack provides a unified dashboard for managing multiple cloud platforms.

• It offers automation and orchestration capabilities to simplify cloud management.

• Corestack also provides governance and compliance features to ensure security and regulatory compliance.

• Some of Corestack's customers include Wipro, HCL, and Tech Mahindra.

Reverse a dictionary in Python

• Create a new dictionary with values as keys and keys as values

• Use dictionary comprehension to create the new dictionary

• If there are duplicate values, use a list comprehension to create a list of keys

• Use the built-in function 'reversed' to reverse the order of the keys or values

I use Git for version control in my projects.

• I create a Git repository for the project

• I commit changes regularly with descriptive messages

• I use branches for new features or bug fixes

• I merge branches back into the main branch when ready

• I use tags to mark important milestones or releases

Authentication is the process of verifying the identity of a user or system.

• Authentication ensures that only authorized users have access to a system or application.

• It involves the use of credentials such as usernames and passwords, or other methods like biometrics.

• Examples of authentication include logging into a website or accessing a secure network.

• Authentication is often followed by authorization, which determines what actions a user is allowed to perform.

reang is not a recognized term in Python development.

• reang is not a Python keyword, module, or function.

• There is no known reference or documentation for reang in Python.

• It is possible that reang is a typo or a mispronunciation of another term.

A while loop is a control flow statement that allows code to be executed repeatedly based on a condition.

• The loop continues until the condition becomes false

• The condition is checked before each iteration

• The loop body must include a way to modify the condition to avoid an infinite loop

Wrapper class is a class that wraps around a primitive data type and provides additional functionality.

• Wrapper classes in Python include int, float, str, etc.

• They allow primitive data types to be used as objects.

• Example: int is a wrapper class for integer data type.

Open source refers to software that is freely available for anyone to use, modify, and distribute.

• Open source software allows for collaboration and transparency in development.

• Examples of open source software include Linux, Apache, and Mozilla Firefox.

• Open source licenses typically allow for the free use, modification, and distribution of the software.

• Open source communities often provide support and resources for users and developers.

Python is a high-level programming language known for its simplicity and readability.

• Python is an interpreted language, meaning it does not need to be compiled before running.

• It has a large standard library that provides many pre-built functions and modules.

• Python supports multiple programming paradigms, including procedural, object-oriented, and functional programming.

• It is widely used in web development, data analysis, artificial intelligence, and scientific computing.

• Pytho...read more

Namespace is a container that holds identifiers (names) used to avoid naming conflicts.

• Namespace is created at different moments and has different lifetimes.

• Python implements namespaces as dictionaries.

• There are four types of namespaces in Python: built-in, global, local, and non-local.

• Namespaces can be accessed using the dot (.) operator.

• Example: 'import math' creates a namespace 'math' that contains all the functions and variables defined in the math module.

Program to generate a particular series

• Define the series pattern

• Use loops to generate the series

• Store the series in an array

• Print the array

for loop is used for iterating over a sequence while while loop is used for executing a block of code repeatedly as long as a condition is true

• For loop is used when the number of iterations is known, while loop is used when the number of iterations is unknown

• For loop is more concise and readable for iterating over sequences like lists, while loop is more flexible for complex conditions

• Example: for i in range(5): print(i) - prints numbers 0 to 4, while example: x = 0; while x ...read more

A function in Python is defined using the 'def' keyword followed by the function name and parameters.

• Use the 'def' keyword followed by the function name and parameters enclosed in parentheses.

• Indent the function body to define the code block.

• Use the 'return' statement to return a value from the function.

• Example: def greet(name): print('Hello, ' + name)

• Example: def add_numbers(a, b): return a + b

Convert two lists into a dictionary.

• Use zip() function to combine the two lists.

• Pass the combined list to dict() function to create a dictionary.

• Use a loop to iterate through the dictionary and print the key-value pairs.

Function to determine if a number is prime or not.

• Check if the number is less than 2, return False if so

• Iterate from 2 to the square root of the number, checking for divisibility

• If no divisors found, return True (number is prime)

Create a function to find the least repeating consecutive character in a string.

• Iterate through the string and keep track of consecutive characters and their counts

• Find the character with the least count of consecutive repetitions

• Return the character with the least count

Call by value passes a copy of the variable's value, while call by reference passes a reference to the variable's memory location.

• Call by value passes a copy of the variable's value, so changes made to the parameter inside the function do not affect the original variable.

• Call by reference passes a reference to the variable's memory location, so changes made to the parameter inside the function affect the original variable.

• In Python, all function arguments are passed by refere...read more