Unit 1, Lesson 1
In Progress
Set
Ruby’s Arrays are remarkably flexible and useful data structures. But they aren’t always the right choice for a collection of items. In this episode, we’ll see why using a data abstraction that enforces uniqueness can prevent bugs while making code more expressive of its intent.
Video transcript & code
In lieu of a transcript, the final Ruby code is provided, along with references.
References
Code
require "set"
class Friend
def self.all
@all ||= {}
end
def self.import(contacts)
contacts.each do |contact|
friend = all[contact[:name]] ||= new(contact[:name])
friend.handles[contact[:service]] = contact[:handle]
friend.tags.merge(contact[:tags])
end
end
attr_accessor :name, :handles, :tags
def initialize(name)
@name = name
@handles = {}
@tags = Set.new
end
def add_tags(*tags)
self.tags |= tags
end
def merge_with(other)
self.handles.merge!(other.handles)
self.tags.merge(tags)
end
end
Friend.import([
{name: "Avdi Grimm", service: "Twitter", handle: "@avdi", tags: ["tech", "flowers"]},
{name: "Avdi Grimm", service: "Instagram", handle: "avdi.grimm", tags: ["flowers", "poetry"]}
])
avdi = Friend.all["Avdi Grimm"]
avdi
# => #"@avdi", "Instagram"=>"avdi.grimm"},
# @name="Avdi Grimm",
# @tags=#>
avdi.add_tags("tech", "cat pics")
avdi.tags
# => #
other = Friend.new("Avdi")
other.handles["Twitch"] = "avdicodes"
other.tags = ["tech", "livecoding"]
avdi.merge_with(other)
avdi.handles
# => {"Twitter"=>"@avdi", "Instagram"=>"avdi.grimm", "Twitch"=>"avdicodes"}
avdi.tags
# => #
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