Set Checker

set_checker.rb

def set?(*cards)
  shapes = cards.map(&:shape).uniq
  colours = cards.map(&:colour).uniq
  fills = cards.map(&:fill).uniq
  count = cards.map(&:count).uniq

  [shapes, colours, fills, count].all? do |attribute|
    attribute.length.odd?
  end
end

Card = Struct.new(:shape, :colour, :fill, :count)

card_1 = Card.new(:diamond, :purple, :lined, :two)
card_2 = Card.new(:oval, :purple, :blank, :two)
card_3 = Card.new(:squiggle, :purple, :filled, :two)
set?(card_1, card_2, card_3)
=> true


card_4 = Card.new(:diamond, :purple, :lined, :two)
card_5 = Card.new(:oval, :purple, :blank, :two)
card_6 = Card.new(:squiggle, :purple, :lined, :three)
set?(card_4, card_5, card_6)
=> false