Practice Arena

Python Coding
Challenges

Write real Python in the browser. Instant feedback. From beginner to expert.

819 challenges 506 easy 280 medium 33 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

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

Flatten nested JSON

Write a function that flattens nested JSON objects into a flat dictionary with dot-separated keys, handling lists and empty objects.

json recursion dictionaries

Data Formats & Parsing medium

Unflatten JSON dict

Given a flat dictionary with keys like 'a.b.c', reconstruct the nested dictionary where each dotted segment becomes a nested level.

json dict parsing

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

Showing 4 challenges · medium · Data Formats & Parsing

Data Formats & Parsing — Python coding challenges

What you will find here

This page lists data formats & parsing challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.

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.