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Lists & Arrays easy

Running Maximum

Implement a function that returns a list where each element is the largest value seen so far.

lists cumulative maximum

Lists & Arrays easy

Zip lists into pairs

Write a function that takes two lists and returns a list of two-element sublists pairing elements by index up to the shortest length.

zip lists pairs

Lists & Arrays easy

Middle Element of an Odd-Length List

Implement a function that returns the middle element of an odd-length list.

lists indexing basic

Lists & Arrays easy

Is Subset of Another List

Write a function that returns True if every element in a given list exists in another list, ignoring duplicates.

subset membership lists

Lists & Arrays easy

Unzip pairs into two lists

Write a function that takes a list of pairs and returns two separate lists: first elements and second elements.

zip unpacking lists

Lists & Arrays easy

Generate a Multiplication Table

Build a function that returns an n x n multiplication table as a list of lists.

nested-loops list-comprehension matrix

Lists & Arrays easy

Majority Element Finder

Implement a function that returns the majority element in a list, which appears more than half the time.

majority frequency arrays

Lists & Arrays easy

Union of Two Lists

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

Lists & Arrays easy

Difference of Two Lists

Write a function that returns items in list a that are not in list b, preserving order and duplicates.

lists difference counting

Lists & Arrays easy

Last occurrence index

Implement a function that returns the last index of a given value in a list, or -1 if the value is not present.

lists indexing search

Lists & Arrays easy

Cartesian Product Pairs

Create a function that returns the Cartesian product of two lists as a sorted list of lists.

lists tuples sorting

Lists & Arrays easy

Reorder list halves

Implement reorder_list(nums) that returns the first half followed by the reversed second half.

lists slicing reversal

Lists & Arrays easy

Insertion Sort

Implement insertion sort that sorts a list in-place and returns the same list.

sorting in-place algorithms

Lists & Arrays easy

Running Total Window

Implement a function that returns a list of running totals, resetting to zero after each positive sum.

running-total sliding-window arrays

Lists & Arrays easy

Boolean Mask Filter

Write a function that filters a list using a boolean mask and returns the matching elements as a list.

mask filter list

Showing 1–15 of 15 challenges · easy · 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.