Group names by first letter
Given a list of names, return a dictionary mapping each first letter to all names starting with that letter in original order.
Anagram Dictionary Groups Lite
Group a list of words into anagrams using a dictionary keyed by sorted characters.
Group by Department
Implement a function that groups a list of employee dictionaries by department, returning a dictionary keyed by department with lists of employee dictionaries.
Pivot sales by product
Write a function that pivots sales records into a dictionary keyed by product with monthly totals.
Top N per group
Implement top_n_per_group that returns the top N scores for each group from a list of (group, score) pairs.
Vertical Order Traversal
Compute the vertical order traversal of a binary tree, grouping nodes by column and row.
Showing 1–6 of 6 challenges
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.