Lesson 1: Tables, arrays and files that do not lose rows
20 min read·13 Oct 2026
Module 2 · Lesson 1 · About 40 minutes · Needs: Module 1, Lesson 1 (Python lists, dicts and functions)
The situation
Dev sends you three exports: the customers, their orders, and the help-centre articles. Priya adds forty support tickets, each labelled by a human agent. Everything arrives as Python dicts and lists; the assistant you build in Module 7 needs it all as clean tables.
Priya's first question is concrete: what has Aisha Rahman (cust-88) bought, which of her orders ship free, and how long is a typical ticket in each category? With arrays and tables that takes seconds, and the same code works on two million rows.