200+ Python Developer Interview Questions and Answers

The logic of the program is to reverse a given string word by word without using any built-in function.

• Split the string into an array of words using whitespace as the delimiter.

• Iterate through the array of words in reverse order.

• Append each word to a new string, separated by a space.

Variables are names given to memory locations while objects are instances of a class with attributes and methods.

• Variables are used to store values while objects are used to represent real-world entities.

• Variables can be reassigned to different values while objects have a fixed identity.

• Variables are created when they are assigned a value while objects are created using constructors.

• Variables can be of different data types while objects are instances of a specific class.

• Examp...read more

Answers to interview questions for a Python developer.

• 1. Tuples are immutable while lists are mutable.

• 2. Decorators are functions that modify the behavior of other functions.

• 3. 'to' object is not a standard term in Python, so it's unclear.

• 4. Pass does nothing, break exits the loop, and continue skips to the next iteration.

• 5. Need the given program to identify the error.

• 6. Explain your projects in detail, highlighting your role and achievements.

To convert a .txt file into a .csv file in Python, you can use the csv module.

• Import the csv module

• Open the .txt file in read mode

• Open a new .csv file in write mode

• Use csv.reader to read the .txt file line by line

• Use csv.writer to write each line to the .csv file

To check if a key exists in a dictionary without raising a KeyError.

• Use the 'in' keyword to check if the key exists in the dictionary.

• Use the 'get' method to return a default value if the key does not exist.

• Use the 'keys' method to get a list of all keys and check if the key is in the list.

Mutable objects can be changed after creation, while immutable objects cannot be changed.

• Mutable objects: lists, dictionaries, sets

• Immutable objects: strings, tuples, numbers

• Example: list is mutable - can be modified by adding/removing elements

• Example: tuple is immutable - cannot be modified once created

Deep copy creates a new object and recursively copies all the objects it references, while shallow copy creates a new object and references the same objects as the original.

• Deep copy creates a completely independent copy of an object, including all nested objects.

• Shallow copy creates a new object, but references the same nested objects as the original.

• Deep copy is useful when you want to modify one object without affecting the other.

• Shallow copy is useful when you want to cre...read more

SOAP is a protocol, while REST is an architectural style for web services.

• SOAP is a protocol that uses XML for message format and relies on a predefined set of standards (WSDL, SOAP, etc.)

• REST is an architectural style that uses standard HTTP methods (GET, POST, PUT, DELETE) and supports multiple data formats (JSON, XML, etc.)

• SOAP is more rigid and requires more bandwidth due to its XML format, while REST is more flexible and lightweight

• SOAP is commonly used in enterprise app...read more

Yes, the key of a dictionary in Python can be changed. The criteria for selecting a key are immutability and uniqueness.

• The key of a dictionary can be any immutable data type such as strings, numbers, or tuples.

• The key must be unique within the dictionary, as duplicate keys are not allowed.

• Changing the value of a key is allowed, but changing the key itself requires creating a new key-value pair.

• Keys that are mutable, such as lists, cannot be used as dictionary keys.

To get the value for a key from a dictionary in Python, use the square bracket notation or the get() method.

• Use square brackets and the key name to access the value directly: dictionary[key]

• Alternatively, use the get() method to retrieve the value: dictionary.get(key)

• If the key is not present in the dictionary, using square brackets will raise a KeyError, while get() will return None or a default value if specified

Method overriding in Python is when a subclass provides a specific implementation of a method that is already provided by its parent class.

• In method overriding, a subclass can provide a specific implementation of a method that is already defined in its parent class.

• The method in the subclass should have the same name, parameters, and return type as the method in the parent class to override it.

• Method overriding allows for polymorphism, where a subclass can be treated as its p...read more

Python 3.10 added new features like structural pattern matching, improved error messages, and more.

• Structural pattern matching allows for more concise and readable code

• Improved error messages make debugging easier

• New syntax for specifying precise types

• Performance improvements in various areas

• New modules and libraries added

• Examples: match case, improved error messages, improved typing syntax

Yes, I have worked on various python projects including web development, data analysis and automation.

• Developed a web application using Django framework

• Automated data extraction and analysis using pandas library

• Created a chatbot using Python and Dialogflow API

• Implemented machine learning algorithms for predictive analysis

• Integrated Python scripts with other technologies like AWS and Docker

A brief explanation of linked list, array, multidimensional array, nested for loop, and polymorphism.

• Linked list is a data structure where each element points to the next one.

• Array is a collection of elements of the same data type stored in contiguous memory locations.

• Multidimensional array is an array with more than one dimension.

• Nested for loop is a loop inside another loop.

• Polymorphism is the ability of an object to take on many forms.

A decorator is a design pattern in Python that allows modifying the behavior of a function or class without changing its source code.

• Decorators are functions that take another function as an argument and return a new function.

• They are used to add functionality to an existing function or class.

• They can be used to modify the behavior of a function, such as adding logging or timing functionality.

• They can also be used to enforce security or access control.

• A decorator is denoted b...read more

Agree, taking time to learn the new domain is crucial for success.

• Learning the new domain will help us understand the business requirements better.

• It will also help us identify potential challenges and opportunities.

• We can leverage our existing skills and knowledge to build better solutions.

• Taking time to learn the new domain will also help us build credibility with stakeholders.

• We can use this time to network and build relationships with experts in the new domain.

A class is a blueprint for creating objects that have properties and methods. Functions are written inside a class to define its behavior.

• A class is a user-defined data type that encapsulates data and functions that operate on that data.

• Functions written inside a class are called methods and are used to define the behavior of the class.

• The role of a class is to provide a template for creating objects that share common properties and behavior.

• Classes allow for code reusability...read more

Lists are mutable while tuples are immutable in Python.

• Lists use square brackets [] while tuples use parentheses ().

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

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

• Lists are generally used for large collections of data while tuples are used for smaller collections or for data that should not be changed.

• Lists are slower than tuples in terms of...read more

Discussing approaches to solve a DSA problem in a Zoom call.

• Understand the problem statement and constraints.

• Choose an appropriate data structure and algorithm.

• Implement the solution and test it with sample inputs.

• Optimize the solution if possible.

• Discuss the time and space complexity of the solution.

Generators in Python are functions that can be paused and resumed, allowing for efficient memory usage and lazy evaluation.

• Generators are created using the yield keyword

• They are used to create iterators

• Generators produce a sequence of values on-the-fly

• They are memory efficient as they generate values one at a time

• Generators are useful for processing large datasets or infinite sequences

Using 3L and 5L vessels, achieve 1L and 4L of water through filling and pouring methods.

• Fill the 3L vessel completely and pour it into the 5L vessel.

• Fill the 3L vessel again and pour it into the 5L vessel until it is full, leaving 1L in the 3L vessel.

• To achieve 4L in the 5L vessel, fill the 5L vessel completely from the water source.

Answers to common Python interview questions.

• Namespace is a container for storing variables and functions.

• Dictionary is a collection of key-value pairs.

• Type conversion is the process of converting one data type to another.

• Arrays are homogeneous while lists are heterogeneous.

• Functions are blocks of code that perform a specific task.

Data can be sent to the database using SQL queries or an ORM like Django's ORM.

• Use SQL queries to insert, update or delete data in the database.

• Use an ORM like Django's ORM to interact with the database using Python code.

• Ensure that the data being sent is properly formatted and validated to prevent errors or security issues.

Pickling is a way to serialize Python objects, while non-pickling refers to objects that cannot be pickled.

• Pickling is used to convert Python objects into a byte stream that can be stored or transmitted.

• Non-pickling objects are those that cannot be serialized using the pickle module.

• Examples of non-pickling objects include file objects, network sockets, and database connections.

• To make an object picklable, it must be able to be reduced to a string of bytes and then reconstruc...read more

Inheritance is a way to create a new class by inheriting properties and methods from an existing class.

• It allows code reusability and saves time.

• Types of inheritance are single, multiple, multilevel, and hierarchical.

• Single inheritance involves inheriting properties and methods from a single parent class.

• Multiple inheritance involves inheriting properties and methods from multiple parent classes.

• Multilevel inheritance involves inheriting properties and methods from a parent c...read more

Python uses automatic memory management through a garbage collector.

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

• When an object's reference count reaches zero, it is automatically deallocated.

• Python also employs a garbage collector to handle cyclic references.

• The garbage collector identifies and collects objects that are no longer reachable.

• Memory management in Python is transparent to the developer.

Collection data types are data structures that can hold multiple values in Python.

• List: ordered, mutable collection

• Tuple: ordered, immutable collection

• Set: unordered, mutable collection with no duplicate elements

• Dictionary: unordered, mutable collection of key-value pairs