Programming Ruby 3.3

Enumerator

Nearly every Enumerable method that takes a block argument can also be called without a block, in which case the method returns an Enumerator. (There are a few subclasses of Enumerator that you wouldn’t create by hand but which implement some specialized logic.) In addition to those Enumerable methods, you can create an enumerator in a few other ways.

Creating Enumerators

Any object can be converted into an Enumerator with the Object#to_enum(method = :each, *args) method (aliased as enum_for). The first argument to to_enum is a symbol that’s the name of a method that converts the object to something enumerable. Any further arguments to to_enum are passed to the method named in the first argument. You can then treat that enumerator ...