Ruby哈希组合

Question

对于一个电子商务应用程序，我试图将一个选项的散列（每个选项都有一个选项数组）转换为一个表示这些选项组合的散列数组。例如：

# Input:
{ :color => [ "blue", "grey" ],
  :size  => [ "s", "m", "l" ] }
# Output:
[ { :color => "blue", :size => "s" },
  { :color => "blue", :size => "m" },
  { :color => "blue", :size => "m" },
  { :color => "grey", :size => "s" },
  { :color => "grey", :size => "m" },
  { :color => "grey", :size => "m" } ]

输入可能有额外的选项，每个选项的选择数量不确定，但它只能嵌套1级深。任何

Answer 1

以上的变体：

input = { color: [ "blue", "grey" ],
          size:  [ "s", "m", "l" ],
          wt:    [:light, :heavy] }
keys = input.keys
  #=> [:color, :size, :wt]
values = input.values
  #=> [["blue", "grey"], ["s", "m", "l"], [:light, :heavy]]
values.shift.product(*values).map { |v| Hash[keys.zip(v)] }
  #=> [{:color=>"blue", :size=>"s", :wt=>:light},
  #    {:color=>"blue", :size=>"s", :wt=>:heavy},
  #    {:color=>"blue", :size=>"m", :wt=>:light},
  #    {:color=>"blue", :size=>"m", :wt=>:heavy},
  #    {:color=>"blue", :size=>"l", :wt=>:light},
  #    {:color=>"blue", :size=>"l", :wt=>:heavy},
  #    {:color=>"grey", :size=>"s", :wt=>:light},
  #    {:color=>"grey", :size=>"s", :wt=>:heavy},
  #    {:color=>"grey", :size=>"m", :wt=>:light},
  #    {:color=>"grey", :size=>"m", :wt=>:heavy},
  #    {:color=>"grey", :size=>"l", :wt=>:light},
  #    {:color=>"grey", :size=>"l", :wt=>:heavy}]

Answer 2

您可以尝试：

ary = input.map {|k,v| [k].product v}
output = ary.shift.product(*ary).map {|a| Hash[a]}

结果：

[
  {:color=>"blue", :size=>"s"},
  {:color=>"blue", :size=>"m"},
  {:color=>"blue", :size=>"l"},
  {:color=>"grey", :size=>"s"},
  {:color=>"grey", :size=>"m"},
  {:color=>"grey", :size=>"l"}
]

Answer 3

您基本上是在尝试计算组合，这意味着有两个级别的迭代，可以聚合这些操作的结果：

input = {:color=>["blue", "grey"], :size=>["s", "m", "l"]}
combinations = input[:color].flat_map do |color|
  input[:size].collect do |size|
    { color: color, size: size }
  end
end
puts combinations.inspect
# => [{:color=>"blue", :size=>"s"}, {:color=>"blue", :size=>"m"}, {:color=>"blue", :size=>"l"}, {:color=>"grey", :size=>"s"}, {:color=>"grey", :size=>"m"}, {:color=>"grey", :size=>"l"}]

这里flat_map派上了用场，因为它折叠了内部膨胀的结果。

Answer 4

请尝试OCG选项组合生成器。

require "ocg"
generator = OCG.new(
  :color => %w[blue grey],
  :size  => %w[s m l]
)
puts generator.next until generator.finished?

Generator包含更多功能，可以帮助您处理其他选项。