問題：
What's the most efficient way to test if an array contains any element from a second array?測試數組是否包含來自第二個數組的任何元素的最有效方法是什麼？
Two examples below, attempting to answer the question does foods contain any element from cheeses :下面的兩個例子試圖回答這個問題， foods含有cheeses任何元素：
cheeses = %w(chedder stilton brie mozzarella feta haloumi reblochon)
foods = %w(pizza feta foods bread biscuits yoghurt bacon)
puts cheeses.collect{|c| foods.include?(c)}.include?(true)
puts (cheeses - foods).size < cheeses.size
解決方案：
參考一： https://en.stackoom.com/question/GXTl參考二： https://stackoom.com/question/GXTl