Initials from a Full Name
Return the uppercase initials of each word in a given full name.
Is pangram?
Implement is_pangram(s) to return True if the string contains every letter from 'a' to 'z' at least once, ignoring case and non-alphabetic characters.
Remove Duplicates from String
Given a string, return a new string with each character that repeats consecutively reduced to a single occurrence.
Longest Word Finder
Write a function that extracts alphabetic words from a string and returns the longest one, with ties broken by earliest position.
Abbreviate Name
Create a function that takes a full name and returns an abbreviated version with initials and the last name.
Mask email address
Given an email address, return a masked version that hides everything but the first and last character of the local part and the domain.
Find substring index
Implement a function that returns the starting index of the first occurrence of a substring using only basic string indexing and slicing.
Sort characters in string
Write a function that sorts the characters in a string and returns the sorted string.
Most Common Character
Return the character that appears most frequently in a string, breaking ties by earliest occurrence.
Find all anagrams
Return all starting indices where any anagram of a given word appears as a substring.
Substring Anagrams
Return all start indices in a string where a substring of length k is an anagram of a pattern string.
Longest Palindrome Substring
Given a string s, return the longest substring that reads the same forwards and backwards.
Index of First Occurrence
Implement a function that finds the starting index of a substring within a string, returning -1 when absent.
Safe Command Executor
Implement emulate_run that simulates running a command list and returns output and exit code.
Parse Log Line
Write a function that parses a log line and returns a dictionary with timestamp, level, and message.
Split on camelCase
Given a camelCase string, split it into words at uppercase letters and return them as lowercase words.
Validate username format
Implement a function that validates a username according to length, allowed characters, and no consecutive underscores.
Change directory manager
Implement a function that processes `cd` commands and returns the resulting absolute path.
Parse markdown headers
Write a function that parses markdown headers and returns their levels and texts.
Parse bullet list
Parse a markdown-style bullet list and return the list of item texts, stripping bullet markers and trimming surrounding whitespace.
Parse numbered list
Take a string containing a numbered list and return a clean list of the item texts.
Find repeated words
Return a lowercase list of unique words that appear more than once across a given text, ignoring case.
Crawler Log Folder
Given a list of folder navigation operations, compute the minimum steps required to return to the main folder.
Two Sum
Return indices (i, j) with i < j such that nums[i] + nums[j] == target.
Showing 73–96 of 371 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.