Previous Weekday Finder
Given a date, return the date of the immediately preceding weekday (Monday–Friday).
Week Number ISO
Given a date, return its ISO 8601 week number (1–53) without using datetime.isocalendar().
Schedule conflict check
Write a function that takes a list of time intervals and returns True if any two overlap.
Month End Date
Implement a function that returns the last day of the month for a given year and month.
Month Start Date
Parse a date string and return the first day of its month in the same format.
Easter Date Calculator
Implement a function that returns the date of Easter Sunday for a given year using the Gregorian computus algorithm.
Parse email header
Write a function that parses a raw email header string and returns sender, recipient, and subject.
Inner Join Two Tables
Write a function that inner joins two lists of dictionaries on a common key and returns the combined rows.
Create Table Schema
Write a function that creates a SQLite table with a given name and columns, and returns the resulting schema as a list of column definitions.
Index Creation Query
Create an in-memory SQLite database, execute CREATE INDEX statements, and return the resulting index metadata rows.
Second highest salary
Given an employees table, write a SQL query that returns the second highest distinct salary, or NULL if it doesn't exist.
Nth Highest Salary
Write a Python function using SQLite to return the Nth highest distinct salary from an employee table.
Customers Never Order
Given Customers and Orders tables, return the names of customers with no orders, sorted alphabetically, or None if all have ordered.
Select All Users
Write a function that connects to an in-memory SQLite database and returns all users as a list of lists.
Dot product of two vectors
Return sum of element-wise products.
Mean of a vector
Return arithmetic mean or 0.0 when empty.
Maximum element in vector
Return largest value or None when empty.
Minimum element in vector
Return smallest value or None when empty.
Sum each matrix row
Given rows, return each row sum.
Sum each matrix column
Return column totals for a rectangular matrix.
Square each element
Return element-wise squares.
Absolute value per element
Return element-wise absolute values.
Keep positive elements
Return values strictly greater than zero.
Prefix sum vector
Return running totals for each prefix of the vector.
Showing 337–360 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.