Leap Year Checker
Implement a function that decides whether a year is a leap year according to the standard Gregorian rules.
Validate date format
Return True if input string is exactly YYYY-MM-DD and a real calendar date.
Validate Password Strength
Implement a function that validates password strength based on clear rules.
Validate time format
Check whether a given string is a valid 24-hour time in HH:MM format.
Validate username format
Implement a function that validates a username according to length, allowed characters, and no consecutive underscores.
Revenue by Month
Write a function that groups a list of (date, amount) pairs by year-month and returns total revenue per month as a sorted dictionary.
Delete Old Records
Filter a list of records by removing those with a date older than a given cutoff date.
Validated descriptor
Implement a TypedField descriptor that raises TypeError if the value is not of the expected type.
Class-based decorator with call validation
Build a class-based decorator that validates a single argument's type and logs successful invocation.
Validate Email Regex
Implement a function that validates email addresses using regex with specific rules.
Validate phone number
Write a function that uses regular expressions to determine if a given string is a valid US phone number.
Match IPv6 Address
Write a function that uses a regex to validate whether a string is a fully expanded IPv6 address.
Match Credit Card Pattern
Write a function that validates a credit card number string against a set of formatting rules.
Validate Hex Color Code
Write a function that validates hex color codes using regular expressions.
Zeller Congruence Weekday
Implement a function that returns the weekday name for a given date using Zeller's congruence.
Validate BST
Implement a function to determine if a binary tree is a valid Binary Search Tree.
Validate Stack Sequences
Given two sequences of distinct integers, verify whether the second sequence is a valid pop order for a stack given the first sequence as push order.
Days in month
Write a function that returns the number of days in a given month and year, correctly handling leap years.
Format date output
Parse ISO date strings and format them into a friendly US-style date output.
Days Between Dates
Write a function that returns the number of days between two given dates.
Add Days to Date
Given a date in YYYY-MM-DD format and an integer number of days, return the resulting date in the same format.
Weekday from date
Write a function that returns the full English weekday name for a date string.
Leap Years in Range
Write a function that returns a list of all leap years between two given years, inclusive.
Age in years months days
Given birth and reference dates, return age as a dictionary with years, months, days.
Showing 1–24 of 42 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.