Hashes

A hash is Ruby's dictionary — with a symbol-key shortcut

Ruby's hash does the same job as Swift's [String: Any] or a JS object. With symbol keys — the common case — Ruby has a shorthand that drops the => entirely:

walker = { name: "Luna", city: "Austin", price_cents: 2500 }

Read name: "Luna" as "the key :name maps to \"Luna\"" — it's exactly :name => "Luna" under the hood, just shorter to write. This is the form you'll see everywhere in Ruby and Rails.