100 Best Python Interview Questions: Beginner, Intermediate, and Advanced

Python is one of the most popular programming languages in the world, and it’s widely used in web development, data science, machine learning, automation, and more. Whether you’re a beginner, intermediate, or advanced Python developer, preparing for interviews can be challenging. To help you out, we’ve compiled a list of 100 Python interview questions categorized into beginner, intermediate, and advanced levels. We’ll also provide a detailed explanation for each category.

1. Beginner-Level Python Interview Questions

These questions are designed to test your foundational knowledge of Python. They cover basic syntax, data types, and simple programming concepts.

1.1 Basic Syntax and Data Types

1. What is Python, and what are its key features?
2. How do you comment in Python?
3. What are Python’s built-in data types?
4. What is the difference between == and is in Python?
5. How do you convert a string to an integer in Python?
6. What is the difference between list and tuple?
7. How do you create an empty dictionary in Python?
8. What is the purpose of the len() function?
9. How do you concatenate two strings in Python?
10. What is the difference between append() and extend() in lists?

1.2 Control Flow

11. How do you write a for loop in Python?
12. What is the difference between break and continue?
13. How do you write an if-else statement in Python?
14. What is a while loop, and how does it work?
15. How do you use the range() function in Python?

1.3 Functions

16. How do you define a function in Python?
17. What is the purpose of the return statement?
18. What is the difference between def and lambda functions?
19. How do you pass arguments to a function?
20. What is the scope of a variable in Python?

1.4 File Handling

21. How do you open and read a file in Python?
22. What is the difference between read(), readline(), and readlines()?
23. How do you write to a file in Python?
24. What is the purpose of the with statement in file handling?
25. How do you handle exceptions in Python?

1.5 Basic Libraries

26. What is the purpose of the math module in Python?
27. How do you generate random numbers in Python?
28. What is the datetime module used for?
29. How do you use the os module in Python?
30. What is the purpose of the sys module?

2. Intermediate-Level Python Interview Questions

These questions test your understanding of more complex Python concepts, such as object-oriented programming, modules, and error handling.

2.1 Object-Oriented Programming (OOP)

31. What is a class in Python?
32. How do you create an object in Python?
33. What is the difference between a class and an object?
34. What is inheritance in Python?
35. What is method overriding in Python?
36. What is the purpose of the super() function?
37. What is encapsulation in Python?
38. What is polymorphism in Python?
39. What is the difference between __init__ and __new__?
40. What are decorators in Python?

2.2 Modules and Packages

41. What is the difference between a module and a package?
42. How do you import a module in Python?
43. What is the purpose of __init__.py in a package?
44. How do you create a Python package?
45. What is the difference between import module and from module import *?

2.3 Error Handling

46. What is the difference between syntax errors and exceptions?
47. How do you handle multiple exceptions in Python?
48. What is the purpose of the finally block?
49. How do you raise an exception in Python?
50. What is the difference between try-except and try-finally?

2.4 Data Structures

51. What is a set in Python, and how is it different from a list?
52. How do you remove duplicates from a list in Python?
53. What is a dictionary comprehension in Python?
54. How do you sort a dictionary by value in Python?
55. What is the difference between deepcopy and shallow copy?

2.5 Intermediate Libraries

56. What is the purpose of the collections module?
57. How do you use the itertools module in Python?
58. What is the functools module used for?
59. How do you use the json module in Python?
60. What is the purpose of the re module?

3. Advanced-Level Python Interview Questions

These questions are designed to test your deep understanding of Python, including advanced concepts like generators, decorators, and concurrency.

3.1 Advanced OOP

61. What is a metaclass in Python?
62. How do you implement multiple inheritance in Python?
63. What is the purpose of the __slots__ attribute?
64. What is the difference between __getattr__ and __getattribute__?
65. How do you implement a singleton pattern in Python?

3.2 Generators and Iterators

66. What is a generator in Python?
67. How do you create a generator function?
68. What is the difference between a generator and an iterator?
69. What is the purpose of the yield keyword?
70. How do you use the next() function with generators?

3.3 Decorators and Context Managers

71. What is a decorator in Python?
72. How do you create a custom decorator?
73. What is the purpose of the @staticmethod decorator?
74. What is a context manager in Python?
75. How do you create a custom context manager?

3.4 Concurrency and Parallelism

76. What is the difference between threading and multiprocessing in Python?
77. How do you use the threading module in Python?
78. What is the Global Interpreter Lock (GIL) in Python?
79. How do you use the asyncio module in Python?
80. What is the difference between synchronous and asynchronous programming?

3.5 Advanced Libraries

81. What is the purpose of the logging module in Python?
82. How do you use the unittest module in Python?
83. What is the purpose of the pickle module?
84. How do you use the subprocess module in Python?
85. What is the purpose of the typing module?

3.6 Performance Optimization

86. How do you profile Python code?
87. What is the purpose of the timeit module?
88. How do you optimize Python code for performance?
89. What is the difference between list and array in Python?
90. How do you use the memory_profiler module?

3.7 Advanced Concepts

91. What is the purpose of the __call__ method in Python?
92. How do you implement operator overloading in Python?
93. What is the purpose of the __annotations__ attribute?
94. How do you use the enum module in Python?
95. What is the purpose of the abc module?

3.8 Python Internals

96. How does Python manage memory?
97. What is the difference between CPython and Jython?
98. How do you use the gc module in Python?
99. What is the purpose of the dis module?
100. How do you contribute to the Python open-source community?

4. How to Prepare for Python Interviews

1. Understand the Basics: Make sure you have a strong grasp of Python fundamentals, including syntax, data types, and control flow.
2. Practice Coding: Solve coding problems on platforms like LeetCode, HackerRank, and Codewars.
3. Learn OOP Concepts: Understand object-oriented programming principles, as they are frequently tested in interviews.
4. Explore Advanced Topics: Study advanced Python concepts like decorators, generators, and concurrency.
5. Work on Projects: Build real-world projects to demonstrate your practical skills.
6. Mock Interviews: Practice mock interviews to get comfortable with the interview format.

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5. Conclusion

Preparing for Python interviews requires a combination of theoretical knowledge and practical skills. By mastering the concepts covered in these 100 Python interview questions, you’ll be well-equipped to tackle interviews at any level. Remember to practice regularly, work on projects, and stay updated with the latest Python trends.