Master Python Interview Essentials: 150+ Questions & Answers

Introduction

While preparing for interviews, the author collected numerous Python interview questions, found many outdated or incomplete, and decided to create a thorough analysis to help readers understand concepts beyond the questions themselves.

What you will learn

Master Python basic syntax

Common Python application scenarios

Use of closures and decorators

Generators and iterators

Common design patterns

Differences between shallow and deep copy

Threads, processes, and coroutines

Meta‑programming and reflection in Python

Typical data structures and algorithms

Crawling and basic network programming

All Questions

Language Features

1. Differences between Python and other languages 2. Explain interpreted vs compiled languages 3. Types of Python interpreters and their characteristics 4. Differences between Python 3 and Python 2 5. int vs long in Python 2/3 6. xrange vs range

Coding Standards

7. What is PEP 8? 8. Do you know the Zen of Python? 9. What are docstrings? 10. What are type annotations? 11. Naming conventions for Python objects 12. Types of comments in Python 13. How to add elegant function comments? 14. How to comment variables? 15. Can tabs and spaces be mixed for indentation? 16. Can multiple modules be imported in a single import statement? 17. Naming considerations for .py files 18. Tools for enforcing Python code style

Data Types

String

19. List basic data types in Python 20. Distinguish mutable vs immutable types 21. Capitalize "hello world" to "Hello World" 22. Check if a string contains only digits 23. Reverse the string "ilovechina" 24. Common string formatting methods 25. Trim leading and trailing spaces from a string 26. Get the last two characters of "123456" 27. Convert a GBK‑encoded string to UTF‑8 28. Split "info:xiaoZhang 33 shandong" into ['info','xiaoZhang','33','shandong'] using regex 29. Convert a string to lowercase 30. Difference between single, double, and triple quotes 31. Reduce multiple spaces in "你好    中国 " to a single space

List

32. Remove duplicates from AList = [1,2,3,1,2] 33. Convert "1,2,3" to ["1","2","3"] 34. Find common and different elements between two lists A and B 35. Flatten [[1,2],[3,4],[5,6]] to [1,2,3,4,5,6] in one line 36. Merge [1,5,7,9] and [2,2,6,8] 37. Shuffle a list

Dictionary

38. Difference between del and pop 39. Sort a dictionary by age

d1 = [
    {'name':'alice', 'age':38},
    {'name':'bob', 'age':18},
    {'name':'Carl', 'age':28},
]

40. Merge a = {"A":1,"B":2} and b = {"C":3,"D":4} 41. Create a dictionary using a comprehension 42. Convert tuples ("a","b") and (1,2) into {"a":1,"b":2}

Comprehensive

43. Common Python data structures and their characteristics

Operations

44. Swap two variables 45. Differences between read, readline, and readlines 46. JSON serialization supported types and customizing datetime handling 47. Preserve Chinese characters when serializing to JSON 48. Merge two files containing letters into a sorted file 49. Compute the date N days after a given date 50. Write a higher‑order function that multiplies its argument by n 51. Identify issues in the provided strappend function and improve it

def strappend(num):
    str='first'
    for i in range(num):
        str+=str(i)
    return str

52. One‑line code to output all even numbers between 1 and 100 53. Purpose of the with statement with example 54. Convert between Python dict and JSON string 55. Count uppercase letters in a file

Advanced Features

56. Purpose of function decorators 57. Python garbage collection mechanism 58. Usage of the magic method __call__ 59. Determine if an object is a function or a method 60. Differences between @classmethod and @staticmethod 61. Implement interfaces in Python 62. Understanding reflection in Python 63. Role and use cases of metaclasses 64. Usage of hasattr, getattr, setattr 65. List common magic methods and their purposes 66. Determine an object's type 67. Does Python pass arguments by value or by reference? 68. Example of using a metaclass 69. Explain any() and all() 70. Use filter to extract odd numbers from a list and build a new list 71. What is monkey patching? 72. How does Python manage memory? 73. Is all memory released when Python exits?

Regular Expressions

74. Extract URL from

www.baidu.com

75. Replace "98" with "100" in a string using re.sub 76. Difference between (.*) and (.*?) 77. Write a regex to match email addresses

Other Topics

78. Purpose of the pass statement 79. Understanding input() 80. Difference between is and == 81. Scope in Python 82. Ternary operator syntax and use cases 83. Usage of enumerate 84. List five standard Python modules 85. Set a global variable inside a function 86. Example usage of pathlib 87. Simple exception handling example 88. Maximum recursion depth and how to overcome it 89. Method Resolution Order (MRO) in OOP 90. When to use isinstance 91. Purpose of assert statements 92. Lambda expression syntax and scenarios 93. Difference between new‑style and old‑style classes 94. What does dir() do? 95. Control import of specific modules from a package 96. List five Python exception types and their meanings 97. Difference between copy and deepcopy 98. Meaning and usage of *args and **kwargs 99. Naming conventions for single‑underscore and double‑underscore prefixes/suffixes 100. Differences among w, a+, and wb file modes 101. Difference between sort and sorted 102. What are negative indices? 103. Purpose of the pprint module 104. Assignment operators in Python 105. Logical operators in Python 106. Bitwise operators in Python 107. Using numbers in different bases 108. Multiple variable assignment syntax

Algorithms and Data Structures

109. Compare worst‑case time complexity of searching for 4 in a list vs a set 110. Compare worst‑case time complexity of inserting 4 in a list vs a set 111. Implement binary search in Python 112. Implement a singleton pattern 113. Generate Fibonacci sequence 114. Find duplicate numbers in a list 115. Find the unique number in a list where others appear twice 116. Write bubble sort 117. Write quick sort 118. Write topological sort 119. Implement binary calculations 120. Rearrange a sequence of '+' and '-' so that all '+' are on the left 121. Reverse a singly linked list 122. Find intersection point of two linked lists 123. Implement a stack using a queue 124. Find median of a data stream 125. Find the k‑th smallest element in a BST

Crawling Related

126. Difference between requests.content and requests.text 127. Brief usage of lxml module 128. Workflow of Scrapy 129. Scrapy deduplication principle 130. Types of Scrapy middlewares you have used 131. Common anti‑scraping measures and solutions 132. Why use proxies? 133. Handling dead proxies 134. Common HTTP headers and their meanings 135. Process of accessing a webpage with a browser 136. Dealing with captchas when crawling too fast 137. Difference between Scrapy and scrapy‑redis; why choose Redis 138. Main problems solved by distributed crawling 139. Multi‑process vs multi‑threaded crawling and reasons 140. Most used parsers for HTML parsing 141. Handling login pages with IP, cookie, and session restrictions without headless browsers 142. Solving captchas (simple image processing vs complex click/drag) 143. Common databases used with crawlers (MySQL, MongoDB, Redis) and their characteristics

Network Programming

144. Difference between TCP and UDP 145. Brief description of three‑way handshake and four‑way termination 146. What is packet sticking (粘包) and its causes

Concurrency

147. Example of using ThreadPoolExecutor from concurrent.futures 148. Differences among multithreading, multiprocessing, and coroutines 149. Explanation of the GIL 150. Inter‑process communication methods 151. Purpose of I/O multiplexing 152. Differences among select, poll, and epoll models 153. Definition of concurrency vs parallelism 154. Explanation of asynchronous non‑blocking I/O 155. Role of threading.local

Git Interview

156. Common Git commands 157. How to view changes in a specific commit