Programming Ruby 3.3

Chapter 4Collections, Blocks, and Iterators

Most real programs have to manage collections of data: the people in a course, the songs in your playlist, the books in the store, and so on. Ruby comes with two classes that are commonly used to handle these collections: arrays and hashes. A Ruby array is an ordered collection of data. A Ruby hash is a key/value pair, equivalent to a Python dictionary, a Java Map, or a JavaScript object. Mastery of these two classes, and their large interfaces, is an important part of being an effective Ruby programmer.

But it isn’t only these two classes that give Ruby its power when dealing with collections. Ruby also has a block syntax that lets you encapsulate chunks of code. When paired with collections, these ...