Parse numbered list
Take a string containing a numbered list and return a clean list of the item texts.
Decode base64 string
Write a function that decodes a base64 string to its original UTF-8 text without using the base64 module.
Parse Version SemVer
Write a function that parses a semantic version string into its numeric components.
Compare Version Strings
Given two version strings, compare them numerically by splitting on dots and ignoring leading zeros.
Parse path segments
Implement a function that parses a path string into clean segments, ignoring slashes, empty parts, and dot segments.
Parse coordinate pairs
Parse a string of coordinate pairs into a list of coordinate lists.
Parse range notation
Parse a comma-separated list of ranges and individual numbers, expanding each range into its full sequence.
Parse Boolean Strings
Implement a function that parses a boolean string into a Python bool, handling True/False/Yes/No/1/0 case-insensitively.
User Friendly Message
Given a raw user input, format it into a single clean sentence with proper sentence case and trimming.
Find repeated words
Return a lowercase list of unique words that appear more than once across a given text, ignoring case.
ROT13 transform
Implement the ROT13 cipher on a string, preserving case and leaving non-letters unchanged.
Crawler Log Folder
Given a list of folder navigation operations, compute the minimum steps required to return to the main folder.
Parse Hex Dump
Write a function that parses a hex dump string into a list of integers.
Caesar Cipher Decrypt
Write a function that decrypts a Caesar cipher by shifting letters backward by a given key.
First non-repeating character
Find the index of the first character that appears only once.
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.
Keys Sorted by Value Descending
Given a dictionary mapping strings to integers, return a list of keys sorted by value descending, and when values tie, alphabetically ascending.
Anagram Dictionary Groups Lite
Group a list of words into anagrams using a dictionary keyed by sorted characters.
Anagram Groups by Size
Group a list of words into anagram groups and return them sorted by group size and lexicographically.
Top K Frequent Words
Given a list of words, return the k most frequent words sorted by frequency (descending) and then alphabetically.
Ransom Note Builder
Given two strings, determine if the ransom note can be formed from the words in the magazine.
Pivot sales by product
Write a function that pivots sales records into a dictionary keyed by product with monthly totals.
String Representation Mixin
Implement a mixin class that provides generic __repr__ and __str__ based on instance attributes.
Valid parentheses
Return True if brackets in the string close in the correct order.
Showing 97–120 of 159 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.