Python 150 Interview Questions and Answers for Fresher in 2025

1. What is Python?

Python is a high-level, interpreted programming language known for its simplicity and readability. It supports multiple programming paradigms and has a large standard library. Python is widely used in web development, automation, data science, and more.  

2. What are the key features of Python?

Python is easy to learn, open-source, and dynamically typed. It supports object-oriented and functional programming and has vast libraries for various tasks. Its syntax is clean, which makes coding faster and easier. 

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

Lists are mutable, meaning you can change their contents, whereas tuples are immutable. Lists use square brackets [ ] and tuples use parentheses ( ). Tuples are generally faster and used for fixed data.                                                                                                                                                                          

4. How is Python interpreted?

Python code is executed line-by-line by the Python interpreter. It converts the source code into bytecode and then executes it using the Python Virtual Machine. This makes Python an interpreted language.                                                                                                                               

5. What are Python’s data types?

 Python has several built-in data types like int, float, str, list, tuple, dict, set, and bool. These types help store different kinds of data in variables. You can also define custom data types using classes.                                                                                                                                                                                  

6. What is PEP 8?

 PEP 8 is the official style guide for Python code. It defines how Python code should be formatted to improve readability. It covers naming conventions, indentation, line length, and more.                                                                                                                                                                             

7. What are Python functions?

 Functions in Python are reusable blocks of code that perform specific tasks. They are defined using the def keyword and can take arguments and return values. Functions help make code modular and easier to maintain.     

8. What is the difference between is and == in Python?

The == operator checks if two variables have the same value, while is checks if they refer to the same object in memory. For example, a == b may be True, but a is b might be False. Use is for identity comparison and == for value comparison.      

9. What is indentation in Python?

Indentation in Python is used to define blocks of code. Unlike other languages that use braces {}, Python uses whitespace. Incorrect indentation leads to syntax errors.     

10. What are Python keywords?

 Keywords are reserved words in Python that have special meaning and cannot be used as variable names. Examples include if, else, for, while, class, and def. There are around 35 keywords in Python.                                                                                                                                                                                            

11. How do you write comments in Python?

 Single-line comments start with a # symbol, and multi-line comments can be written using triple quotes ”’ or “””. Comments help explain the code and are ignored by the interpreter. They’re useful for code documentation.        

12. What is a variable in Python?

 A variable is a name used to store data in memory. In Python, you don’t need to declare the type of variable explicitly. The type is inferred from the value assigned to it.       

13. What is type conversion in Python?                                                                                    Type conversion is the process of changing one data type to another, like int to float or str to int. Python supports implicit and explicit type conversion. Functions like int(), float(), and str() are used for this.

14. What are Python loops?

Python supports for and while loops to perform repetitive tasks. for loops iterate over a sequence, while while loops continue as long as a condition is true. Loops can be controlled using break and continue.

15. What is the difference between break and continue?

break exits the loop completely, while continue skips the current iteration and moves to the next one. Both are used to control the flow inside loops. They’re useful for optimizing loop behavior.

16. What are Python strings?

 Strings are sequences of characters enclosed in quotes. They are immutable, meaning their content cannot be changed. Python provides many methods to manipulate strings like upper(), lower(), and replace().

17. How do you handle exceptions in Python?

 Python uses try, except blocks to handle exceptions and prevent program crashes. You can also use finally for cleanup actions. This makes error handling smoother and more controlled.

18. What is a dictionary in Python?

 A dictionary is a collection of key-value pairs enclosed in {}. Keys must be unique and immutable, while values can be of any type. It’s used to store data in a structured and fast-access format.

19. What is a module in Python?

 A module is a file containing Python code such as functions, variables, and classes. You can import it into other programs using the import statement. Python has many built-in modules like math and random.

20. What is the difference between local and global variables?

 A local variable is defined inside a function and is accessible only within that function. A global variable is declared outside functions and is accessible throughout the program. You can use the global keyword to modify a global variable inside a function.

21. What is a class in Python?

 A class is a blueprint for creating objects. It defines attributes and behaviors (methods) common to all objects of that type. You define a class using the class keyword.

22. What is an object in Python?

 An object is an instance of a class with its own data and functions. Objects are created from classes using the class constructor. They help organize code using object-oriented programming.

23. What is inheritance in Python?

 Inheritance is a feature that allows one class (child) to inherit properties and methods from another class (parent). It promotes code reuse and improves maintainability. Python supports single and multiple inheritance.

24. What is the use of self in Python?

 self refers to the instance of the class and is used to access variables and methods of the current object. It must be the first parameter in instance methods. It helps differentiate between class variables and local variables.

25. What are Python lambda functions?

 Lambda functions are anonymous functions defined using the lambda keyword. They can have any number of arguments but only one expression. They’re often used for short, throwaway functions.

26. What is recursion in Python?

Recursion is a function calling itself to solve a smaller part of the problem. It continues until a base condition is met. Python allows recursion but has a recursion limit to prevent infinite loops.

27. What is the difference between append() and extend() in Python lists?

 append() adds a single element to the end of the list, while extend() adds all elements from another iterable. append() adds the whole object, extend() adds individual elements. Both modify the original list.

28. What are Python sets?

 A set is an unordered collection of unique items in Python, defined with curly braces {}. It doesn’t allow duplicates and supports mathematical operations like union and intersection. Sets are useful for filtering and comparing data.

29. What is the purpose of the pass statement in Python?

 The pass statement does nothing and is used as a placeholder. It’s useful when a statement is required syntactically but you don’t want any code to run. It avoids syntax errors in empty code blocks.

30. How do you create a virtual environment in Python?

 You can create a virtual environment using the python -m venv env_name command. It isolates project dependencies from the system Python installation. Activate it with source env_name/bin/activate or env_name\Scripts\activate.

31. What is the use of the with statement in Python?

 The with statement simplifies resource management like opening and closing files. It ensures that resources are properly released, even if an error occurs. It is commonly used with file operations.

32. What is slicing in Python?

Slicing lets you extract parts of a sequence like lists, strings, or tuples. It uses the syntax sequence[start:stop:step]. It helps retrieve sub-parts without modifying the original data.

33. What is the difference between remove() and pop() in lists?

 remove() deletes the first matching value, while pop() removes the item at a specific index and returns it. remove() does not return anything, but pop() does. Both modify the original list.

34. What is the purpose of id() in Python?

 The id() function returns the unique identifier of an object, which corresponds to its memory address. It helps check if two variables point to the same object. It’s useful for debugging and identity checks.

35. What are mutable and immutable data types in Python?

 Mutable types like lists and dictionaries can be changed after creation. Immutable types like strings, tuples, and integers cannot be changed. Choosing the right type depends on whether data should be modifiable.

36. What is list comprehension?

 List comprehension is a concise way to create lists using a single line of code. It uses a loop and optional condition inside square brackets. It improves readability and performance.

37. How do you install packages in Python?

 You use the pip command, like pip install package_name, to install Python packages. It fetches and installs packages from the Python Package Index (PyPI). Pip is the standard package manager for Python.

38. What is the purpose of __init__() method in classes?

 The __init__() method is the constructor in Python classes. It runs automatically when a new object is created and is used to initialize attributes. It helps set up objects with initial data.

39. What is a Python iterator?

An iterator is an object that allows you to loop over a sequence one element at a time. It implements __iter__() and __next__() methods. You can create custom iterators in classes too.

40. What is the difference between == and != in Python?

 == checks if two values are equal, and != checks if they are not equal. These are comparison operators used in conditional statements. They return Boolean values: True or False.

41. How do you handle multiple exceptions in Python?

 You can handle multiple exceptions using multiple except blocks or by grouping them in a tuple. This ensures specific or general errors are caught appropriately. It helps make code more robust.

42. What is the use of range() in Python?

The range() function generates a sequence of numbers and is often used in loops. It can take 1 to 3 arguments: start, stop, and step. It returns a range object, which is memory efficient.

43. What is the purpose of the dir() function?

 dir() returns a list of all valid attributes of an object. It’s useful for introspection and debugging. It helps you discover the methods and variables available for any object.

44. What are Python decorators?

 Decorators are functions that modify the behavior of other functions or methods. They are applied using the @decorator_name syntax. Decorators are commonly used for logging, authorization, and caching.

45. What is a Python generator?

Generators are functions that yield values one at a time using the yield keyword. They are memory-efficient because they don’t store all items in memory. You iterate through them like lists.

    46. What are *args and kwargs in Python?

*args allows a function to accept any number of positional arguments, and **kwargs accepts any number of keyword arguments. They help create flexible functions. Both are useful in advanced function definitions.

47. What is the use of enumerate() in Python?

enumerate() adds a counter to an iterable and returns it as an enumerate object. It’s useful when you need both index and value in a loop. It enhances readability and performance.

48. What is the difference between isinstance() and type()?

 type() returns the exact type of an object, while isinstance() checks if an object is of a specified type or its subclass. isinstance() is more flexible and recommended for type checking.

49. What is the use of zip() in Python?

 zip() combines elements from multiple iterables into tuples. It’s useful for parallel iteration over two or more sequences. The result is an iterator of tuples.

50. What is the purpose of map() in Python?

 map() applies a function to all items in an iterable and returns a map object. It allows for functional-style processing of sequences. It’s often used with lambda for compact code.

51. What is the difference between filter() and map() in Python?

 map() applies a function to all elements of an iterable, while filter() returns elements that match a condition. filter() keeps only the items for which the function returns True. Both return iterators.

52. What is docstring in Python?

 A docstring is a special string written inside triple quotes right after defining a function, class, or module. It describes what the function or module does. You can access it using the __doc__ attribute.

53. What is the difference between return and print() in Python?

 print() displays the result on the screen, while return sends the result back to the caller. return is used to pass data out of functions. print() is used mainly for debugging or user output.

54. What is the purpose of globals() and locals()?

 globals() returns a dictionary of global variables, while locals() returns a dictionary of local variables. They are useful for introspection and debugging. You can also use them to dynamically access variables.

55. What is a namespace in Python?
    A namespace is a container that holds variable names and their values. Python has different namespaces: local, global, and built-in. It helps avoid name conflicts and manages scope.                                                                                                                                       
56. What are Python’s built-in data structures?
    Python has four main built-in data structures: lists, tuples, sets, and dictionaries. Each has unique characteristics for storing and manipulating data. They’re the foundation for handling collections.                                                                                         
57. What is a shallow copy vs. deep copy?

 A shallow copy creates a new object but references the same inner objects, while a deep copy creates new inner objects too. Use copy() for shallow and deepcopy() from copy module for deep. Deep copy ensures full duplication.

58. What is the use of del in Python?

 The del keyword is used to delete variables, list items, or dictionary entries. It frees memory by removing references. It can also delete slices in lists.

59. What is the purpose of __name__ == “__main__” in Python?

 It checks whether a Python script is being run directly or imported as a module. If it’s run directly, the block inside runs. It helps control code execution.

60. How do you read a file in Python?

 You use the open() function with mode ‘r’ to read a file. Then, use .read(), .readline(), or .readlines() to get content. Always close the file using .close() or a with statement.