Practice Arena

Python Coding
Challenges

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925 challenges 556 easy 323 medium 46 hard

All Easy Medium Hard

All Python Basics Strings & Text Lists & Arrays Dicts & Sets Functions & Closures OOP & Classes Data Structures & Algorithms Advanced Python Iterators & Generators Decorators & Context Managers Error Handling & Exceptions Regular Expressions Math & Number Theory Bit Manipulation Dynamic Programming Trees & Binary Trees Graphs & Graph Algorithms Recursion & Backtracking Greedy Algorithms Binary Search Two Pointers & Sliding Window Stacks & Queues Heaps & Priority Queues Linked Lists Matrix & 2D Arrays Datetime & Time Calculations Data Formats & Parsing SQL & SQLite Numpy & Vectorized Computing Cryptography & Hashing

Datetime & Time Calculations easy

Format date output

Parse ISO date strings and format them into a friendly US-style date output.

datetime string-formatting date-parsing

Datetime & Time Calculations easy

Weekday from date

Write a function that returns the full English weekday name for a date string.

datetime date weekday

Datetime & Time Calculations easy

Time Difference HH:MM

Given two times in HH:MM format, return the absolute difference as a string in HH:MM format.

datetime time string

Datetime & Time Calculations easy

Unix timestamp to datetime

Write a function that returns a UTC datetime string from a Unix timestamp.

datetime unix-timestamp utc

Datetime & Time Calculations easy

Datetime to Unix timestamp

Parse a datetime string and convert it to a Unix timestamp assuming UTC.

datetime parsing timestamp

Datetime & Time Calculations easy

Quarter from date

Compute the quarter (1-4) for a date string like '2023-07-15'.

datetime date parsing

Datetime & Time Calculations easy

Duration Human Readable

Write a function that turns a number of seconds into a human-readable duration like '2 hours, 1 minute'.

datetime strings formatting

Datetime & Time Calculations easy

Month Start Date

Parse a date string and return the first day of its month in the same format.

datetime date-parsing formatting

Data Formats & Parsing medium

Extract JSON-like numbers

Parse a simplified JSON-like string without using the json module and sum all numbers found in it.

json parsing numbers

Data Formats & Parsing medium

Base64 Encode/Decode

Implement two functions to encode and decode Base64 strings using the standard alphabet and padding.

base64 encoding string

Data Formats & Parsing easy

Protocol definition

Parse a simple wire protocol string into a structured dictionary.

parsing protocol strings

Data Formats & Parsing easy

Config Parser Reader

Parse a simple INI-style configuration text into a nested dictionary.

parsing strings config

Data Formats & Parsing easy

Generate CSV row

Implement a function that converts a list of values into a single CSV row with correct quoting and escaping.

csv escaping strings

Data Formats & Parsing easy

Parse email header

Write a function that parses a raw email header string and returns sender, recipient, and subject.

parsing strings email

Data Formats & Parsing easy

Encode Base64 String

Write a function that encodes a UTF-8 string into a base64 string without using the base64 module.

base64 encoding strings

Data Formats & Parsing medium

Serialize dict to TOML-like

Convert nested Python dicts into a simplified TOML-like string with sorted keys, type-aware formatting, and flat table sections.

dict toml serialization

Data Formats & Parsing medium

Base64 Encode Decode

Implement Base64 encoding and decoding functions that handle padding and all standard characters.

base64 encoding decoding

Data Formats & Parsing easy

Parse CSV Row

Implement a robust function that parses a single CSV line into a list of fields, handling double quotes and escaped quotes.

csv parsing strings

Data Formats & Parsing easy

Parse Apache log line

Write a function that parses a single Apache access log line into a dictionary with IP, timestamp, request, status, and size.

parsing strings regex

Data Formats & Parsing easy

Parse table rows

Implement a function that converts a simple text table into a list of dictionaries.

parsing strings csv

Cryptography & Hashing easy

SHA256 Hash String

Write a function that returns the SHA256 hexadecimal digest of a given string.

hashing sha256 hashlib

Cryptography & Hashing easy

Compute SHA-1 Hash String

Write a function that returns the SHA-1 hash of a string as a 40-character hex string.

sha1 hashlib hashing

Cryptography & Hashing easy

Constant Time Compare

Write a function that compares two strings without leaking length or content via timing.

constant-time security comparison

Cryptography & Hashing easy

SHA1 Hash String

Implement a function that returns the SHA1 hexadecimal digest of an input string.

sha1 hashlib hashing

Showing 193–216 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.