Compound interest
Return the future balance after compound interest, rounded to two decimals.
Grade from Score
Write a function that maps a numeric score to its letter grade using standard grading thresholds.
Grade Calculator
Implement a function that converts a numeric score to a letter grade using a standard scale.
Map, Filter, Reduce
Implement three functions using map, filter, and reduce to manipulate a list of integers.
Variadic Sum Function
Implement a variadic function that sums an arbitrary number of numeric arguments.
Guess Number Game
Simulate a number guessing game with attempts, feedback, and a win/lose result.
Invariant checker
Implement check_invariant(a, b, c) that returns True when a equals b plus c and False otherwise, matching the given examples.
Bind First Argument
Implement bind_first_arg, a decorator that fixes the first argument of any function.
Reentrant Lock Manager
Implement a ReentrantLock class with acquire, release, locked, owner, and helper functions that test thread-safety with real threads.
LRU cache decorator
Implement @lru_cache(maxsize=N) for unary functions using OrderedDict.
TypeVar bounded generic
Learn to use TypeVar with bounds to write type-safe generic functions in Python.
Once Decorator: Run a Function Only Once
Implement a decorator that caches and returns the result of the first call for subsequent calls.
Print Args Decorator
Write a decorator that prints function name and arguments, then returns the original result.
Bit Mask Permissions
Implement helper functions to compose bit masks and check permission bits using bitwise operators.
Julian Day Number Converter
Implement two functions to convert between Gregorian calendar dates and Julian Day Numbers using a standard formula.
Base64 Encode/Decode
Implement two functions to encode and decode Base64 strings using the standard alphabet and padding.
Base64 Encode Decode
Implement Base64 encoding and decoding functions that handle padding and all standard characters.
Cumulative Sum SQL
Write a SQL query to compute cumulative sales totals per product ordered by sale date.
Showing 1–18 of 18 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.