Percentile Calculation
Given a list of numbers and a target value, return the percentile rank of that value in the list.
Euclidean Distance Matrix
Write a function to compute the Euclidean distance between every pair of points from two lists.
Cosine Similarity of Vectors
Compute the cosine similarity between two equal-length numeric vectors using pure Python.
Logging Filter
Given a list of log entries, return those matching a given severity level and containing a keyword.
Order by Name
Implement a function that sorts a list of names alphabetically ignoring case, returning a new list.
Invariant checker
Implement check_invariant(a, b, c) that returns True when a equals b plus c and False otherwise, matching the given examples.
Argmax along axis
Write a function that returns index positions of the maximum values along rows or columns of a 2D list.
Min-Max Scaler: Fit and Transform
Implement a MinMaxScaler class that normalizes numeric data to a given range using fit and transform methods.
Validate Password Strength
Implement a function that validates password strength based on clear rules.
Jump Game Minimum Jumps
Given an array of non-negative integers where each element is the maximum jump length, compute the minimum jumps to reach the last index.
Reverse a string
Return the characters of the string in reverse order.
Palindrome check
Return True if the string reads the same forwards and backwards (ignoring case and non-alphanumeric).
Count vowels
Count the number of vowels (a, e, i, o, u) in a string (case-insensitive).
Title case converter
Return the string with each word capitalised.
Anagram check
Return True if two strings are anagrams of each other.
Run-length encoding
Compress consecutive identical characters, e.g. 'aaabbc' → 'a3b2c1'.
Longest common prefix
Find the longest common prefix among a list of strings.
Integer to Roman
Convert a positive integer to its Roman numeral representation.
Zigzag string conversion
Encode a string in zigzag order across numRows rows, then read row by row.
Strip and Collapse Whitespace
Write a function that strips leading/trailing whitespace and collapses inner runs of whitespace to single spaces.
Snake case to camel case
Implement a function that converts snake_case strings to camelCase.
Camel case to snake case
Write a function that converts camelCase input to snake_case while handling acronyms and numbers correctly.
Remove punctuation
Write a function that removes all ASCII punctuation characters from a string.
Is pangram
Write a function that determines whether a given string is a pangram, ignoring case and non-letter characters.
Showing 97–120 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.