Custom iterator class
Implement a custom iterator class that repeatedly yields elements from a list up to a given number of times.
Window Iterator
Implement a generator that yields consecutive windows of a given size from any iterable.
Pairwise Sequence Pairs
Write a generator function pairwise that yields each consecutive overlapping pair from any iterable as lists.
Groupby Consecutive
Write a generator function that yields (value, list_of_occurrences) for each run of consecutive equal items.
Flatten Nested List Iterator
Implement a class that iterates over all integers in a nested list structure in depth-first order.
Iterator protocol class
Implement a class that follows the iterator protocol and yields squared numbers up to a given limit.
Batch Iterator
Implement a generator that yields batches of a given size from any iterable, including the final partial batch.
Zip Longest Fill
Create an iterator that yields lists from multiple iterables, padding with a fill value when lengths differ.
Graph DFS Generator
Implement a generator function that performs a depth-first traversal of a graph without recursion.
Showing 1–9 of 9 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.