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Python Coding
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467 challenges 330 easy 120 medium 17 hard

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Lists & Arrays easy

Second Largest Unique Value

Return the second largest distinct integer from a list, or None if it doesn't exist.

sorting unique arrays

Lists & Arrays easy

All Unique Values Keep Order

Remove duplicates from a list, keeping only the first occurrence of each value while preserving relative order.

deduplicate order list

Lists & Arrays easy

Find Second Largest

Find the second largest unique number in a list, or None if it doesn't exist.

sorting max unique

Lists & Arrays easy

Intersection of Two Lists

Given two lists, return a sorted list of unique elements that appear in both lists.

intersection sorting unique

Lists & Arrays easy

Union of Two Lists

Implement a function that combines two lists and returns only unique elements.

Lists & Arrays medium

Two Missing Numbers

Given a list of n-2 unique integers from 1 to n, find the two missing numbers efficiently.

missing-numbers arrays math

Showing 6 challenges · Lists & Arrays

Lists & Arrays — Python coding challenges

What you will find here

This page lists lists & arrays 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.