100+ Python Software Developer Interview Questions and Answers

Pandas is used in data manipulation due to its ability to handle large datasets, perform data cleaning, and provide powerful data analysis tools.

• Pandas provides a DataFrame object that allows for easy manipulation of tabular data

• It can handle missing data and perform data cleaning operations

• Pandas has powerful data analysis tools such as grouping, filtering, and merging

• It can handle large datasets efficiently

• Pandas integrates well with other Python libraries such as NumPy and...read more

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

• Python is dynamically typed and garbage-collected.

• It supports multiple programming paradigms like procedural, object-oriented, and functional programming.

• Python has a large standard library and a thriving community of developers.

• Example: print('Hello, World!')

The __init__ method is a special method in Python classes used for initializing new objects. __init__.py is a special file used to define a package in Python.

• The __init__ method is called when a new object is created from a class and is used to initialize the object's attributes.

• __init__.py is a special file used to define a package in Python. It can be empty or contain initialization code for the package.

• The __init__.py file is used to indicate to Python that a directory is ...read more

Generators are functions that return an iterator, while iterators are objects that can be iterated over. To find 3 highest salaried employees, sort the employees by salary and select the top 3.

• Generators are functions that use yield keyword to return data one at a time, while iterators are objects that implement __iter__ and __next__ methods.

• To find 3 highest salaried employees, sort the employees by salary in descending order and select the first 3.

• Example: employees = [{'na...read more

Docker is a platform that allows you to package, distribute, and run applications in containers.

• Docker uses containerization technology to create isolated environments for applications to run in

• Containers share the host OS kernel but have their own filesystem and resources

• Docker images are used to create containers, which can be easily distributed and run on any system

• Docker uses a client-server architecture with a daemon running on the host machine

Context managers in Python are objects that enable the execution of code within a specific context, typically used with the 'with' statement.

• Context managers are implemented using the __enter__() and __exit__() methods.

• They are commonly used for resource management, such as file handling or database connections.

• The 'with' statement automatically calls the __enter__() method before the block of code and the __exit__() method after the block of code.

Use ORM query to filter dates within a specified range

• Use the 'filter' method in ORM to specify the date range

• Use the '__range' lookup to specify the start and end dates

• Example: Model.objects.filter(date_field__range=(start_date, end_date))

Coding is the process of creating instructions for a computer to execute, typically using a programming language.

• Coding involves writing and organizing lines of code to create software or applications.

• It requires logical thinking, problem-solving skills, and attention to detail.

• Examples of coding languages include Python, Java, and C++.

Use dynamic programming to find the longest palindrome substring of a given string.

• Use a 2D boolean array to store whether a substring is a palindrome or not.

• Iterate through all possible substrings and update the array accordingly.

• Return the longest palindrome substring found.

SQL queries and ORM in Django for Python Software Developer interview.

• SQL queries can be written in Django using raw() method or by using Django's ORM.

• ORM in Django stands for Object-Relational Mapping, which allows developers to interact with the database using Python objects.

• Example SQL query: SELECT * FROM table_name WHERE column_name = 'value';

• Example ORM query: ModelName.objects.filter(column_name='value')

Object-oriented programming (OOP) is a programming paradigm that uses objects to represent and manipulate data.

• OOP focuses on creating reusable code by organizing data and behavior into objects.

• Encapsulation, inheritance, and polymorphism are key principles of OOP.

• Real-time example: A car can be represented as an object with properties like color, model, and methods like start, stop, and accelerate.

Sort a list without using inbuilt keyword

• Iterate through the list and compare each element with the rest to find the smallest element

• Swap the smallest element with the first element

• Repeat the process for the remaining elements until the list is sorted

Interrupts are signals sent to the CPU to temporarily suspend the current program and handle a specific event or request.

• Interrupts allow the CPU to respond to events in real-time without wasting processing power.

• They can be generated by hardware devices, software programs, or the CPU itself.

• Examples include keyboard input, timer expiration, and hardware errors.

Generators are functions that allow you to iterate over a sequence of items without storing them all in memory. Decorators are functions that modify the behavior of other functions.

• Generators in Python are created using the yield keyword, allowing you to iterate over a sequence of items one at a time.

• Generators are memory efficient as they do not store all items in memory at once.

• Decorators in Python are functions that take another function as an argument and extend its behav...read more

OOPs (Object-Oriented Programming) is a programming paradigm that uses objects to represent and manipulate data.

• Python supports OOPs concepts such as encapsulation, inheritance, and polymorphism.

• Classes and objects are the fundamental building blocks of OOPs in Python.

• Encapsulation allows data hiding and abstraction, ensuring data security and modularity.

• Inheritance enables code reuse and the creation of hierarchical relationships between classes.

• Polymorphism allows objects o...read more

Object-oriented programming concepts in Python include classes, objects, inheritance, encapsulation, and polymorphism.

• Classes: Blueprint for creating objects with attributes and methods.

• Objects: Instances of classes that can store data and perform actions.

• Inheritance: Ability to create a new class based on an existing class.

• Encapsulation: Restricting access to certain components of an object.

• Polymorphism: Ability for objects to take on multiple forms or behaviors.

• Example: cla...read more

Reversing a six digit number using Python

• Convert the number to a string to easily manipulate each digit

• Use string slicing to reverse the order of the digits

• Convert the reversed string back to an integer for the final result

Pytesseract library is used for optical character recognition (OCR) in Python.

• Pytesseract is used to extract text from images and PDFs.

• It can be used for automating data entry tasks.

• It is commonly used in document management systems.

• Pytesseract can be used to extract text from scanned documents.

• It can also be used for text recognition in images captured by cameras.

• Pytesseract is often used in machine learning projects for text recognition.

Yes, tuples are fully immutable in Python.

• Tuples cannot be modified once created.

• Elements of a tuple cannot be changed, added, or removed.

• Attempting to modify a tuple will result in a TypeError.

• Example: tuple1 = (1, 2, 3) - tuple1[0] = 4 will raise a TypeError.

Docker is a platform used to develop, ship, and run applications in containers.

• Docker allows developers to package their applications and dependencies into a container, which can then be easily shared and run on any system.

• Containers created with Docker are lightweight, portable, and isolated from the host system, making them ideal for microservices architecture.

• Docker simplifies the process of deploying and scaling applications, as well as ensuring consistency between develo...read more

MVT architecture stands for Model-View-Template architecture, commonly used in web development with Django framework.

• MVT separates the logic of an application into three components: Model, View, and Template.

• Model represents the data structure, View handles the user interface and business logic, and Template manages the presentation layer.

• MVT is similar to MVC (Model-View-Controller) architecture but with a different naming convention.

• Example: In Django, models.py defines the...read more

Modules are files containing Python code, while packages are directories containing modules.

• Modules are used to organize Python code into reusable files.

• Packages are used to organize modules into directories for better organization.

• Modules can be imported using the 'import' keyword, while packages are imported using dot notation.

• Example: 'import math' imports the math module, while 'import mypackage.mymodule' imports a module from a package.

Pandas is a powerful open-source data manipulation and analysis library for Python.

• Pandas provides data structures like DataFrame and Series for efficient data manipulation.

• It offers tools for reading and writing data in various formats such as CSV, Excel, SQL databases.

• Pandas allows for data cleaning, reshaping, merging, and grouping operations.

• It integrates well with other libraries like NumPy and Matplotlib for data analysis and visualization.

• Example: df = pd.DataFrame(dat...read more

Tuples are immutable and ordered collections, while lists are mutable and ordered collections in Python.

• Tuples are created using parentheses, while lists are created using square brackets.

• Tuples cannot be modified after creation, while lists can be modified.

• Tuples are faster than lists for iteration and accessing elements.

• Lists are more flexible and have more built-in methods compared to tuples.

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

• Python is dynamically typed and uses indentation for code blocks.

• It has a large standard library and supports multiple programming paradigms.

• Python is widely used for web development, data analysis, artificial intelligence, and more.

Apache Airflow is a platform to programmatically author, schedule, and monitor workflows.

• Apache Airflow allows users to define workflows as Directed Acyclic Graphs (DAGs) in Python scripts.

• It provides a web-based UI for users to visualize and monitor the status of their workflows.

• Airflow uses a scheduler to trigger tasks based on their dependencies and schedules.

• It supports various integrations with external systems like databases, cloud services, and more.

• Tasks in Airflow ar...read more

Self-intersection occurs when a curve or surface intersects itself at a point.

• Self-intersection can occur in computer graphics when rendering complex shapes.

• It can also occur in geometry when analyzing curves and surfaces.

• Self-intersection can lead to rendering artifacts or inaccuracies in calculations.

Lists are mutable, ordered collections of items while tuples are immutable, ordered collections of items.

• Lists are defined using square brackets [] while tuples are defined using parentheses ().

• Lists can be modified (add, remove, change elements) while tuples cannot be modified once created.

• Lists are typically used for collections of similar items that may need to be modified, while tuples are used for fixed collections of items.

• Example: list_example = [1, 2, 3] and tuple_exa...read more

Use SQL JOIN to combine rows from two tables based on a related column between them.

• Use JOIN keyword in SQL to combine rows from two tables based on a related column

• Types of JOINs include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN

• Example: SELECT * FROM table1 JOIN table2 ON table1.column = table2.column

Python generator is a function that returns an iterator object which can be iterated over.

• Generators are created using a function with 'yield' statement instead of 'return'.

• They allow you to iterate over a sequence of items without creating the entire sequence in memory at once.

• Generators are memory efficient and can be used to generate an infinite sequence of items.

• Example: def my_generator(): for i in range(5): yield i

• Example: gen = my_generator() print(next(gen)) # Output:...read more

List is mutable, tuple is immutable in Python.

• List uses square brackets [], tuple uses parentheses ().

• Elements in list can be changed, tuple elements are fixed.

• List is slower than tuple due to mutability.

• List is used for dynamic data, tuple for static data.

Elements of Python include variables, data types, operators, control structures, functions, and modules.

• Variables: Used to store data values.

• Data types: Define the type of data that can be stored.

• Operators: Used to perform operations on variables and values.

• Control structures: Determine the flow of execution in a program.

• Functions: Reusable blocks of code that perform a specific task.

• Modules: Collections of functions and variables that can be used in other programs.

Time complexity refers to the amount of time an algorithm takes to run as a function of the input size.

• It measures how the runtime of an algorithm grows as the input size increases.

• Common time complexities include O(1) constant time, O(log n) logarithmic time, O(n) linear time, O(n^2) quadratic time, and O(2^n) exponential time.

• Understanding time complexity helps in analyzing and optimizing algorithms for efficiency.

• Example: A linear search has a time complexity of O(n) as it...read more

Sessions in Flask are used to store user-specific information across multiple requests.

• Sessions are implemented using cookies, which store a session ID on the client side.

• Session data is stored on the server side, typically in a secure and encrypted manner.

• Flask provides a 'session' object that allows you to store and access session data easily.

• You can set session variables using 'session['key'] = 'value' and retrieve them using 'session.get('key').

Dependency injection is a design pattern that allows objects to receive dependencies from external sources rather than creating them internally.

• Dependency injection helps to decouple the code and make it more testable and maintainable.

• It allows for easier swapping of dependencies and promotes code reusability.

• There are three types of dependency injection: constructor injection, setter injection, and interface injection.

• Example: Instead of creating a database connection object...read more

A list in Python can be created by enclosing elements in square brackets []

• Use square brackets [] to enclose elements

• Separate elements with commas

• Elements can be of any data type

• Example: my_list = [1, 'apple', True, 3.14]

A generator function in Python yields values one at a time, allowing for lazy evaluation.

• Use the 'yield' keyword in a function to return values lazily

• Generators are memory efficient as they only compute values as needed

• Example: def lazy_generator(): for i in range(5): yield i

• Call the generator function using next() to get the next value

Microservices are a software development technique where applications are composed of small, independent services that communicate over well-defined APIs.

• Microservices break down a large application into smaller, loosely coupled services.

• Each service is responsible for a specific function and can be developed, deployed, and scaled independently.

• Communication between services is typically done through APIs, often using lightweight protocols like HTTP or messaging queues.

• Micros...read more

ETL pipeline stands for Extract, Transform, Load pipeline used to extract data from various sources, transform it, and load it into a data warehouse.

• ETL pipeline involves extracting data from multiple sources such as databases, APIs, files, etc.

• The extracted data is then transformed by cleaning, filtering, aggregating, and structuring it for analysis.

• Finally, the transformed data is loaded into a data warehouse or database for further analysis and reporting.

• Popular tools for ...read more

ETL Processor is a tool used for Extracting, Transforming, and Loading data from various sources into a target database.

• Use ETL tools like Apache NiFi, Talend, or Informatica to extract data from different sources.

• Transform the data by applying various operations like filtering, aggregating, and joining.

• Load the transformed data into a target database or data warehouse for analysis and reporting.

• Monitor and schedule ETL jobs to ensure data is processed efficiently and accurat...read more

Sort a list with duplicate numbers using Python

• Use the sorted() function to sort the list in ascending order

• To maintain the duplicate numbers, use a lambda function as the key parameter in sorted()

• Example: nums = [3, 1, 4, 1, 5, 9, 2, 6, 5], sorted_nums = sorted(nums, key=lambda x: (x, nums.index(x)))

HTTP is a protocol used for transferring data over the internet. REST API is a set of rules for building web services.

• HTTP stands for Hypertext Transfer Protocol, used for communication between web servers and clients

• REST API (Representational State Transfer) is a set of rules for building web services that adhere to the principles of REST

• RESTful APIs use standard HTTP methods like GET, POST, PUT, DELETE to perform CRUD operations on resources

• REST APIs typically return data i...read more

Namespace in Python is a system to make sure that all the names in a program are unique and can be used without any conflict.

• Namespaces are containers for mapping names to objects.

• Python uses namespaces to avoid naming conflicts and to create a unique space for each variable, function, etc.

• There are different types of namespaces in Python such as local, global, and built-in namespaces.

Scopes in Python refer to the visibility of variables within a program.

• Variables defined inside a function have local scope and are only accessible within that function.

• Global variables can be accessed from any part of the program.

• Nonlocal variables are used in nested functions to access variables from the outer function.

Generators in Python are functions that allow you to iterate over a sequence of items without storing them all in memory at once.

• Generators use the 'yield' keyword to return data one item at a time

• They are more memory efficient compared to lists as they generate values on the fly

• Generators are used in situations where you need to iterate over a large sequence of items without loading them all into memory at once

The existing application follows a microservices architecture with separate components for different functionalities.

• The application is divided into multiple services that communicate with each other through APIs.

• Each service is responsible for a specific task or functionality, promoting modularity and scalability.

• Examples of microservices in the architecture include user authentication service, payment processing service, and notification service.

Kafka is a distributed streaming platform used for building real-time data pipelines and streaming applications.

• Kafka is developed by Apache Software Foundation.

• It is written in Scala and Java.

• Kafka is used for building real-time data pipelines and streaming applications.

• It provides high-throughput, fault-tolerant, and scalable messaging system.

• Kafka is often used for log aggregation, stream processing, event sourcing, and real-time analytics.