Model real data with Python lists, tuples, dictionaries, sets, and comprehensions.
A list can hold anything, which is exactly why beginners put everything in one. Three lists side by side, one for names, one for counts, one for dates, and a silent agreement that position 2 in each means the same seed. It works until somebody sorts one of them. This course is about picking the right shape instead. A tuple for a record that must never change. A dictionary when you want to look something up by name rather than by position. A set when the only question is whether something is already in the group. Sorting by any field somebody asks for. Comprehensions, for when a five-line loop says one thing and can say it in one line. And nested data, because real information is rarely flat. Everything is built on the Seed Library, a community seed-lending catalog that grows through the course: a shelf, then a shelf walked in order, then fixed packet records, then a variety looked up by name, then the duplicate donations removed, then the catalog ranked, then the same reports written short, then beds and plantings two levels deep, and finally the whole catalog. The shape of that data is the subject, and by the end you choose it on purpose.
45 Lessons • 53 Practices • 18 Quizzes • 4 Projects · ~10h Total
Not just theory. You finish this course with real work to show.
This is the same in-browser editor every lesson uses. Edit the code, hit Run.
Run code in the browser and see the result immediately. Every lesson works this way.
Stuck? Puff explains the error and nudges you forward, without giving the answer away.
Streaks, diamonds, and certificates. Your progress saves automatically, forever.
Every completed course issues a certificate with a public verification link.
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One certificate per course. Finish a program and earn its program certificate too.
LinkedIn-ready, with a PDF you can download and attach.
You can write a loop and a function. This is what to put inside them once one value stops being enough.
You use lists for everything and suspect there is a better shape. There is, and this names when each one wins.
The database and web courses ahead run on a list of dictionaries. This is where that becomes ordinary.
Python Data Structures is free to start, no credit card needed. Some later sections are part of Pro, and finishing every section, including the certificate, needs a Pro plan.
Yes, or the equivalent. This course assumes you can write a loop, an if statement and a function, and use lists and f-strings, and it spends all of that from item one without re-teaching it.
When the record is fixed and its positions mean something: a coordinate, a date, a row read from a file. A tuple cannot be edited after it is made, which sounds like a limitation and is really a guarantee, because anything holding one knows it cannot be changed underneath them. A list is the right choice when the collection grows, shrinks or gets reordered.
How this course connects to the bigger picture, and what to explore next.
Free to start, no credit card required. Write real code from the first lesson and keep your progress forever.
Start Learning FreeWriting a loop that builds a collection in one line, when that line is easier to read than the loop. Nothing new is computed. This course teaches both directions, including turning an unreadable comprehension back into a loop, because knowing when not to use one is the harder half.
No. This course is about Python's four built-in containers and choosing between them. Arrays, linked lists, stacks, queues, trees and big-O notation are a different subject, covered by Devpuff's DSA courses, which are taught in JavaScript today rather than Python.
The Seed Library: a lending catalog that starts as one shelf and ends as a nested plan of beds, plantings and per-group totals, with four projects along the way.
Yes, for this course at 100 percent. It also counts towards the Python Developer program certificate, which issues once every course in that program is complete.
Go deeper into Python functions: arguments, scope, lambdas, decorators, generators, and modules.