The Book of Ruby

Hashes

Although arrays provide a good way of indexing a collection of items by number, sometimes it would be more convenient to index them in some other way. If, for example, you were creating a collection of recipes, it would be more meaningful to have each recipe indexed by name, such as “Rich Chocolate Cake” and “Coq au Vin,” rather than by numbers.

Ruby has a class that lets you do just that, called a hash. This is the equivalent of what some other languages call a dictionary or associative array. Just like a real dictionary, each entry is indexed by a unique key (in a real-life dictionary, this would be a word) that is associated with a value (in a dictionary, this would be the definition of the word).

Creating Hashes

Just like an array, you ...