Today I read Ruby's magical Enumerable module from AppSignal. It clearly explains the subject. And It gives a short code for linked list, I like it.
class LinkedList
def initialize(head, tail = nil)
@head, @tail = head, tail
end
def <<(item)
LinkedList.new(item, self)
end
def inspect
[@head, @tail].inspect
end
end
irb> LinkedList.new(73) << 12 << 42
=> [42, [12, [73, nil]]]
And then with a each method and a include, You can make it Enumerable.
class LinkedList
include Enumerable
def initialize(head, tail = nil)
@head, @tail = head, tail
end
def <<(item)
LinkedList.new(item, self)
end
def inspect
[@head, @tail].inspect
end
def each(&block)
block.call(@head)
@tail.each(&block) if @tail
end
end
irb> list = LinkedList.new(73) << 12 << 42
=> [42, [12, [73, nil]]]
irb> list.count
=> 3
irb> list.max
=> 73
irb> list.map { |item| item * item }
=> [1764, 144, 5329]
irb> list.select(&:even?)
=> [42, 12]
I like the gradually way of explaining code. And you?
Top comments (0)