Practice Arena

Python Coding
Challenges

Write real Python in the browser. Instant feedback. From beginner to expert.

925 challenges 556 easy 323 medium 46 hard

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All Python Basics Strings & Text Lists & Arrays Dicts & Sets Functions & Closures OOP & Classes Data Structures & Algorithms Advanced Python Iterators & Generators Decorators & Context Managers Error Handling & Exceptions Regular Expressions Math & Number Theory Bit Manipulation Dynamic Programming Trees & Binary Trees Graphs & Graph Algorithms Recursion & Backtracking Greedy Algorithms Binary Search Two Pointers & Sliding Window Stacks & Queues Heaps & Priority Queues Linked Lists Matrix & 2D Arrays Datetime & Time Calculations Data Formats & Parsing SQL & SQLite Numpy & Vectorized Computing Cryptography & Hashing

Lists & Arrays easy

Generate a Multiplication Table

Build a function that returns an n x n multiplication table as a list of lists.

nested-loops list-comprehension matrix

Lists & Arrays easy

Image channel swap

Implement a function that swaps the red and blue channels of an RGB image.

lists comprehensions rgb

Lists & Arrays easy

Cartesian Product Pairs

Create a function that returns the Cartesian product of two lists as a sorted list of lists.

lists tuples sorting

Lists & Arrays easy

Boolean Mask Filter

Write a function that filters a list using a boolean mask and returns the matching elements as a list.

mask filter list

Showing 1–4 of 4 challenges · Lists & Arrays

Lists & Arrays — Python coding challenges

What you will find here

This page lists lists & arrays challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.

Challenges vs tutorials and quizzes

Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.