Set

# title: Set
# source: https://rosettacode.org/wiki/Set
# category: Rosetta Code
# difficulty: Intro
# summary: Demonstrate union, intersection, and difference with array-backed sets.
# tags: popular, arrays, sets, basics

def set_union(left, right)
  (left + right).uniq
end

def set_intersection(left, right)
  left.select do |value|
    right.include?(value)
  end
end

def set_difference(left, right)
  left - right
end

def run
  left = [1, 2, 3, 4]
  right = [3, 4, 5, 6]

  {
    union: set_union(left, right),
    intersection: set_intersection(left, right),
    difference: set_difference(left, right)
  }
end