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Python Coding Challenges

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925 challenges 556 easy 323 medium 46 hard
Lists & Arrays easy

Rotate List Right by k

Implement a function that rotates a list to the right by k positions.

lists rotation modulo
+8 pts 10m
Lists & Arrays easy

Convert Binary Number List

Given a list of bits (0s and 1s) in most-significant-first order, return the equivalent integer value.

binary lists conversion
+8 pts 10m
Lists & Arrays easy

Intersection two lists length

Return the number of distinct elements that appear in both input lists.

lists sets intersection
+8 pts 10m
Lists & Arrays easy

Flatten Multidimensional Lists

Write a function that flattens arbitrarily nested lists of integers into a single list.

recursion nested-lists flatten
+10 pts 15m
Lists & Arrays easy

Concatenate Horizontally

Write a function that horizontally concatenates two 2D lists into a new 2D list.

lists concatenation matrix
+8 pts 10m
Lists & Arrays easy

Rolling Window Mean

Given a list of numbers and a window size k, return a list of the means of every contiguous subarray of length k.

sliding-window lists averaging
+10 pts 12m
Lists & Arrays easy

Linear Interpolation Array

Given an array with some None values, replace them by linear interpolation between the nearest known values.

arrays interpolation math
+8 pts 12m
Lists & Arrays easy

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.

lists encoding matrices
+10 pts 10m
Lists & Arrays easy

Average Salary by Department

Given a list of employee tuples (name, department, salary), return a dictionary mapping each department to its average salary.

averages dictionaries lists
+10 pts 15m
Lists & Arrays easy

Pad array edges

Implement a function that pads a list on both ends with a given value to a specified total length.

lists padding slicing
+7 pts 10m

Showing 25–34 of 34 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.