Palindromic Number Check
Write a function to check if a given integer is a palindrome.
Hexagonal Number
Write a function to check if a positive integer is a hexagonal number.
Count trailing zeros
Write a function that counts the number of trailing zeros in the decimal representation of a positive integer.
Count Leading Zeros
Write a function that returns the number of leading zeros in a list of integers.
Convolve 1D signal
Implement a 1D convolution function with three modes using pure Python.
Guess Number Game
Simulate a number guessing game with attempts, feedback, and a win/lose result.
Remove Duplicates from Sorted Array
Given a sorted list, remove duplicates in-place and return the new length.
Longest Substring with K Repeating Characters
Return the length of the longest substring of a given string in which every character appears at least K times.
Basic Calculator
Implement a function that evaluates a simple arithmetic expression with +, -, *, / and parentheses.
Copy deep vs shallow
Predict and write a function that returns a copied list and inspect whether nested modification affects the original.
Take n Items
Given a list and a non-negative integer n, return a new list containing the first n elements.
Overlap two intervals
Given two closed intervals, return their overlap as a tuple or None if they do not overlap.
Condition Variable Waiter
Implement a deterministic simulation of a waiter whose tray has limited capacity and who becomes busy for a fixed time after each pickup.
Parse environment variables
Write parse_env_vars that parses KEY=VALUE lines into a dict, converting booleans/numbers and ignoring comments.
Filter by Age
Filter a list of person dictionaries by age and return their names.
Limit and Offset Query
Write a function that returns a page from a dataset given limit and offset.
Insert New Row
Implement a function that inserts a new row into a 2D list at a specified index.
Rank Employees by Salary
Sort a list of employee dictionaries by salary descending, tie-break by name, and return ranked strings.
Array mean and std
Implement the function array_stats that returns the mean and population standard deviation of a list of numbers.
Broadcast Add Scalar
Add a scalar to every number in a 2D list and return a new 2D list without modifying the original.
Fancy Index Select
Given a 2D matrix and a list of row indices, select those rows in order and return them as a new 2D list.
Reshape array dimensions
Implement a function that reshapes a 1D list into a 2D list with given dimensions.
Cumulative Sum Vectorized
Implement a function that returns the cumulative sum of a list of numbers.
Element-wise Clip
Implement a function that clips each element of a list to a specified range.
Showing 73–96 of 925 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.