10 Essential Python Interview Questions and Answers to Test Your Skills

Whether you're applying for a Python web developer, crawler engineer, data analyst, or automation operations role, certain fundamental knowledge is essential. Below are ten typical Python interview questions with explanations and code snippets.

Question 1

Prompt: How would you modify the following Python code so that it calls the show method of class A?

Answer: The focus is class inheritance; you can specify the class object via the __class__ attribute. Add the following code:

Question 2

Prompt: How would you modify the following Python code so that it runs?

Answer: This question tests method objects. To allow an instance to be called directly, implement the __call__ method. Add the following code:

Question 3

Prompt: What is the output of the following code?

Answer:

This question examines the use of __new__ and __init__. __new__ decides which object to return before creation (useful in singleton or factory patterns), while __init__ runs after the object is created.

Question 4

Prompt: What does the following code output?

Answer:

This question tests list and dictionary comprehensions.

Question 5

Prompt: What does the following code output?

Answer:

The question focuses on global vs. local variables. num is not a global variable, so each function gets its own copy. To modify the global num, you must declare it with the global keyword, e.g.:

Question 6

Prompt: How can you swap the values of two variables in a single line of code?

Answer:

Question 7

Prompt: How can you add code so that any undefined method call falls back to a mydefault method?

Answer:

This question tests Python's default method handling. The __getattr__ method is invoked only when an attribute is not defined. To support arguments, add a *args parameter to mydefault:

Question 8

Prompt: A package contains three modules mod1.py, mod2.py, mod3.py. When using from demopack import *, how can you ensure only mod1 and mod3 are imported?

Answer: Add an __init__.py file to the package and define the __all__ list:

Question 9

Prompt: Write a function that takes an integer n and returns another function that returns the product of n and its argument.

Answer:

Question 10

Prompt: What is the hidden issue in the following Python 2 code?

Answer: Because str is an immutable object, each iteration creates a new string object. As num grows, more string objects are created, leading to increased memory consumption.