Reverse Words in a Sentence
Reverse the order of words in a sentence while preserving single spaces between words.
Count consonants
Write a function that counts the number of consonant letters in a string.
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.
Extract digits from string
Write a function that extracts all digit characters from a given string, preserving their original order.
Replace Spaces with Dashes
Write a function that replaces every space in a string with a dash.
Capitalize First Letter
Write a function that capitalizes the first letter of each word in a string.
Snake case converter
Implement a function that converts a string to snake_case according to given rules.
Camel Case Converter
Write a function that converts a space-separated phrase into lower camelCase.
Kebab Case Converter
Implement a function that converts any string to kebab-case, handling spaces, underscores, camelCase, and punctuation.
Count Syllables (Simple)
Count syllables in a word by counting groups of consecutive vowels (a, e, i, o, u).
Is isogram?
Write a function that checks whether a given word is an isogram, ignoring letter case and only considering alphabetic characters.
Rotate String Right
Implement a function that rotates a given string to the right by a specified number of positions, handling shifts larger than the string length.
Compress Consecutive Chars
Write a function that compresses a string by replacing runs of identical characters with the character followed by the count.
Expand compressed string
Implement a function that expands run-length encoded strings (e.g., 'a3b2' → 'aaabb').
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.
Count Substrings
Implement a function that counts non-overlapping occurrences of a substring in a given string.
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.
Roman to Integer
Convert a valid Roman numeral string to an integer using standard rules.
Isomorphic Strings Check
Given two strings, check if they are isomorphic by verifying a one-to-one character mapping.
Showing 49–72 of 219 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.