Move Zeros to the End
Reorder a list in-place, pushing all zeros to the end while preserving the order of non-zero numbers.
Interleave Two Lists
Write a function that interleaves two lists element by element, preserving order.
All Unique Values Keep Order
Remove duplicates from a list, keeping only the first occurrence of each value while preserving relative order.
Move Zeros to End
Rearrange a list by moving all zeros to the end while preserving the relative order of non-zero elements.
Difference of Two Lists
Write a function that returns items in list a that are not in list b, preserving order and duplicates.
Wave sort array
Given a list of integers, reorder it into a wave pattern where elements alternate down-up, and return the new list.
Move Zeroes
Implement move_zeroes(nums) that in-place moves all zeros to the end while maintaining the order of non-zero elements.
Sort array by parity
Given a list of integers, return a new list with all evens first and odds last, preserving original relative order.
Reorder list halves
Implement reorder_list(nums) that returns the first half followed by the reversed second half.
Convert Binary Number List
Given a list of bits (0s and 1s) in most-significant-first order, return the equivalent integer value.
One Hot Encode Labels
Given a list of categorical labels, return a list of one-hot encoded vectors based on the sort order of unique labels.
Showing 1–11 of 11 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.
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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.