Most Asked Python Interview Questions

Top 50 Python Interview Questions With Answers

 1. What is Python, and why is it used?

• Answer: Python is a high-level, interpreted, and general-purpose programming language. It is used for web development, data analysis, artificial intelligence, scientific computing, and more.

2. Explain the difference between Python 2 and Python 3.

• Answer: Python 2 is an older version of Python, while Python 3 is the latest version. Python 3 is not backward compatible with Python 2, as it introduced several syntax and functionality changes.

3. What are the key features of Python?

• Answer: Key features include simplicity, readability, extensive libraries, cross-platform compatibility, and an active community.

4. Explain the Zen of Python (PEP 20).

• Answer: It's a collection of guiding aphorisms for writing computer programs in Python, emphasizing readability and simplicity. Example: "Readability counts."

5. How do you comment in Python?

• Answer: You can use the # symbol to add comments in Python.

6. What is PEP 8?

• Answer: PEP 8 is the style guide for writing clean, readable Python code. It covers naming conventions, indentation, and other coding standards.

7. What are Python data types?

• Answer: Python data types include int, float, str, list, tuple, dict, set, and more.

8. Explain the difference between a list and a tuple.

• Answer: Lists are mutable, and you can change their elements. Tuples are immutable, and their elements cannot be changed.

9. What is a dictionary in Python?

• Answer: A dictionary is a collection of key-value pairs, where each key maps to a value.

10. How do you create a function in Python?

• Answer: You can create a function using the def keyword, followed by the function name and parameters.

11. What is a lambda function?

• Answer: A lambda function is an anonymous function defined using the lambda keyword, often used for simple, one-liner functions.

12. What is a module in Python?

• Answer: A module is a Python script containing functions, classes, and variables, which can be imported and used in other scripts.

13. Explain the use of __init__ in Python classes.

• Answer: __init__ is a special method in Python classes used to initialize object attributes when an instance is created.

14. How do you handle exceptions in Python?

• Answer: You can use try, except, and finally blocks to handle exceptions and provide error-handling code.

15. What is the difference between append() and extend() for lists?

• Answer: append() adds an element to the end of a list, while extend() appends all the elements of an iterable to the list.

16. How can you open and close a file in Python?

• Answer: Use the open() function to open a file and close() method to close it.

17. Explain list comprehension in Python.

• Answer: List comprehension is a concise way to create lists based on existing lists or other iterables.

18. What is the Global Interpreter Lock (GIL)?

• Answer: The GIL is a mutex in CPython (the standard Python implementation) that allows only one thread to execute in a Python process at a time.

19. How can you remove duplicates from a list in Python?

• Answer: You can convert the list to a set to remove duplicates, then convert it back to a list if necessary.

20. What is the difference between deep copy and shallow copy?

• Answer: A deep copy creates a new object with a new copy of the original data, while a shallow copy creates a new object that references the original data.

21. How do you use the map() function in Python?

• Answer: map() applies a function to each item in an iterable (e.g., a list) and returns an iterable with the results.

22. Explain the usage of decorators in Python.

• Answer: Decorators are functions that modify the behavior of other functions or methods. They are often used for logging, authentication, and more.

23. What are Python generators?

• Answer: Generators are functions that use the yield keyword to produce a sequence of values lazily, which saves memory and improves performance.

24. How can you create a virtual environment in Python?

• Answer: Use the venv module to create a virtual environment: python -m venv myenv.

25. What is the purpose of the if __name__ == "__main__": statement?

• Answer: It allows you to determine whether a Python script is being run as the main program or imported as a module.

26. How do you sort a list in Python?

• Answer: You can use the sorted() function or the list.sort() method to sort a list.

27. Explain the difference between == and is in Python.

• Answer: == compares the values of objects, while is compares the identities (memory addresses) of objects.

28. What is the purpose of the with statement in Python?

• Answer: The with statement is used to simplify resource management and ensure that cleanup actions are taken, such as file closing.

29. How can you iterate over a dictionary in Python?

• Answer: You can use a for loop to iterate over a dictionary's keys, values, or key-value pairs using methods like items().

30. What is a list in Python?

• Answer: A list is an ordered collection of elements that can be of different data types.

31. Explain the Global and Local scope of variables in Python.

• Answer: Variables defined outside functions have a global scope, while those defined inside functions have a local scope.

32. How do you create a class in Python?

• Answer: Use the class keyword to define a class, and you can include attributes and methods within it.

33. What is a set in Python?

• Answer: A set is an unordered collection of unique elements.

34. How do you swap the values of two variables in Python?

• Answer: You can use a temporary variable or do it in a single line without a temporary variable: a, b = b, a.

35. What is the __str__ method in Python classes?

• Answer: __str__ is used to define a human-readable string representation of an object. It is called by the str() and print() functions.

36. Explain the concept of method overloading in Python.

• Answer: Python doesn't support method overloading in the traditional sense (as in some other languages), but you can achieve similar behavior using default arguments and variable-length argument lists.

37. How do you perform file I/O in Python?

• Answer: You can use the open() function to open files, read() and write() methods to read and write data, and the close() method to close files.

38. What are docstrings in Python?

• Answer: Docstrings are triple-quoted strings that provide documentation for modules, classes, functions, and methods.

39. How can you handle multiple exceptions in Python?

• Answer: You can use multiple except blocks or a single except block with a tuple of exceptions to handle multiple exceptions.

40. Explain the use of the range() function in Python.

• Answer: The range() function generates a sequence of numbers and is often used in for loops.

41. What is the pass statement in Python?

• Answer: The pass statement is a placeholder statement that does nothing. It's often used for code that will be implemented later.

42. What are list, set, and dictionary comprehensions in Python?

• Answer: Comprehensions are concise ways to create lists, sets, and dictionaries using a single line of code.

43. How do you remove an item from a list by value, and how by index?

• Answer: To remove by value, use the remove() method. To remove by index, use the pop() method.

44. What is the purpose of the __del__ method in Python classes?

• Answer: __del__ is used to define the finalization actions for an object. It's called when the object is about to be destroyed.

45. Explain the use of try, except, else, and finally in exception handling.

• Answer: try is used to enclose the code that might raise an exception, except is used to handle exceptions, else is executed if no exceptions occur, and finally is executed in all cases to ensure cleanup.

46. How can you reverse a string in Python?

• Answer: You can use slicing to reverse a string: s[::-1].

47. Explain the purpose of the super() function in Python.

• Answer: super() is used to call a method from a parent class in a child class, allowing you to extend the parent class's behavior.

48. How do you convert a string to an integer and vice versa in Python?

• Answer: You can use int() to convert a string to an integer and str() to convert an integer to a string.

49. What is the difference between a shallow copy and a deep copy of an object?

• Answer: A shallow copy creates a new object that references the original object's elements. A deep copy creates a new object with a new copy of the original object's elements.

50. How can you use regular expressions in Python?

• Answer: You can use the re module to work with regular expressions in Python, allowing you to search, match, and manipulate text based on patterns.