Chapter 06 — Collections: List, Set, Map

Level: beginner Estimated time: 6 h Prerequisites: Chapter 05 — Loops (for, while, do while) What you will be able to do by the end: create, iterate over, and manipulate List, Set, and Map collections, including nested collections similar to what an API returns, and build a complete game inventory.

06.0 — Chapter objectives

By the end of this chapter, you will be able to:

• understand what a collection is;
• store multiple values in a single variable;
• create a List;
• access the elements of a list;
• modify a list;
• add and remove elements;
• iterate over a list with for;
• iterate over a list with for-in;
• use length, first, last, isEmpty, and isNotEmpty;
• use contains() and indexOf();
• create a Set;
• understand value uniqueness in a Set;
• perform unions, intersections, and differences;
• create a Map;
• understand the key/value principle;
• read, add, update, and remove a Map entry;
• iterate over a Map;
• create nested collections;
• work with structures similar to those received from a JSON API;
• build a simple game inventory.