Practice Arena

Python Coding
Challenges

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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

Strings & Text easy

Parse Hex Dump

Write a function that parses a hex dump string into a list of integers.

hex parsing bytes

Strings & Text easy

Caesar Cipher Decrypt

Write a function that decrypts a Caesar cipher by shifting letters backward by a given key.

strings cipher ascii

Lists & Arrays easy

Chunk a list into n-sized parts

Write a function that divides a list into sublists of at most n elements.

list chunking slicing

Lists & Arrays easy

Rotate Left by k

Implement a function that rotates a list left by k positions.

rotation lists slicing

Lists & Arrays easy

Interleave Two Lists

Write a function that interleaves two lists element by element, preserving order.

lists merge indexing

Lists & Arrays easy

Running Maximum

Implement a function that returns a list where each element is the largest value seen so far.

lists cumulative maximum

Lists & Arrays easy

Insert into a Sorted List

Implement a function that inserts a value into a sorted list at the correct position using binary search.

lists binary-search insertion

Lists & Arrays easy

Zip lists into pairs

Write a function that takes two lists and returns a list of two-element sublists pairing elements by index up to the shortest length.

zip lists pairs

Lists & Arrays easy

Middle Element of an Odd-Length List

Implement a function that returns the middle element of an odd-length list.

lists indexing basic

Lists & Arrays easy

Is Subset of Another List

Write a function that returns True if every element in a given list exists in another list, ignoring duplicates.

subset membership lists

Lists & Arrays easy

Unzip pairs into two lists

Write a function that takes a list of pairs and returns two separate lists: first elements and second elements.

zip unpacking lists

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

Majority Element Finder

Implement a function that returns the majority element in a list, which appears more than half the time.

majority frequency arrays

Lists & Arrays easy

Union of Two Lists

Implement a function that combines two lists and returns only unique elements.

Lists & Arrays easy

Difference of Two Lists

Write a function that returns items in list a that are not in list b, preserving order and duplicates.

lists difference counting

Lists & Arrays easy

Chunk list into groups

Implement a function that splits a list into sublists of a given size.

list slicing chunking

Lists & Arrays easy

Zip Two Lists

Write a function that pairs elements from two lists by index, stopping at the shorter list.

zip lists pairs

Lists & Arrays easy

Rearrange Positives and Negatives

Write a function that rearranges a list in-place so all negative numbers come before non-negative numbers.

in-place two-pointers partition

Lists & Arrays easy

Last occurrence index

Implement a function that returns the last index of a given value in a list, or -1 if the value is not present.

lists indexing search

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

Pad Array Edges

Write a function that pads a list with zeros on both ends.

lists slicing padding

Lists & Arrays easy

Merge Sorted Array In Place

Write a function that merges two sorted arrays into the first array in-place, keeping the result sorted.

arrays sorting in-place

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

Sort List Merge Sort

Write a function that sorts a list of integers using the merge sort algorithm.

merge sort sorting recursion

Showing 121–144 of 286 challenges · easy

Guide: free Python coding challenges

Practice Python by solving problems

PythonSkillset challenges are hands-on coding exercises from beginner to advanced. Open a challenge, read the problem, write Python in the split-pane editor, and run tests with Pyodide — no install required.

How to use the arena

Pick a category — basics, algorithms, strings, and more
Open a challenge, read the statement, and edit the starter code
Run tests, fix failures, then try a related quiz or tutorial lesson

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.