ruby-on-rails - 将一个数组的每个元素连接到 ruby​​ 中另一个数组的每个元素

Question

我有两个数组，我可以将它们循环加入这两个数组。但是有更好的方法吗？

colors = ['yellow', 'green']
shirts = ['s','m','xl','xxl']

需要的输出:

output = ['yellow_s','yellow_m','yellow_xl','yellow_xxl','green_s','green_m','green_x','green_xxl']

Answer 1

使用 Array#product ，可以得到笛卡尔积:

colors = ['yellow', 'green']
shirts = ['s','m','xl','xxl']
colors.product(shirts).map { |c, s| "#{c}_#{s}" }
# => ["yellow_s", "yellow_m", "yellow_xl", "yellow_xxl",
#     "green_s", "green_m", "green_xl", "green_xxl"]

colors.product(shirts).map { |e| e.join("_") }
# => ["yellow_s", "yellow_m", "yellow_xl", "yellow_xxl",
#     "green_s", "green_m", "green_xl", "green_xxl"]