Sum all node values
Add every integer payload in the list.
Maximum node value
Return the largest integer or None when empty.
Remove the head node
Return a new list without the first node.
Toeplitz Matrix Check
Write a function is_toeplitz(matrix) that checks if a 2D list is a Toeplitz matrix, where all elements on the same diagonal from top-left to bottom-right are identical.
Matrix Multiply 2D
Write a function that multiplies two 2D matrices (lists of lists) and returns the product matrix.
Transpose 2D Array
Implement a function that returns the transpose of a rectangular 2D list.
Flipping an Image
Implement a function that flips an image represented as a binary matrix by reversing each row and inverting each pixel.
Leap Years in Range
Write a function that returns a list of all leap years between two given years, inclusive.
Schedule conflict check
Write a function that takes a list of time intervals and returns True if any two overlap.
Time Slot Generator
Generate a list of time slots of a specified duration within a start and end time.
Generate CSV row
Implement a function that converts a list of values into a single CSV row with correct quoting and escaping.
Update Row by ID
Given a list of CSV rows and target ID, replace the first matching row's value.
Parse CSV Row
Implement a robust function that parses a single CSV line into a list of fields, handling double quotes and escaped quotes.
Parse table rows
Implement a function that converts a simple text table into a list of dictionaries.
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.
Select All Users
Write a function that connects to an in-memory SQLite database and returns all users as a list of lists.
Element-wise vector addition
Add equal-length numeric lists element-wise.
Showing 169–186 of 186 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.