Arrays Ruby：多维数组到一维行

在Ruby中，我该如何着手：

[
  1, 
  ["green", "blue", "black"], 
  [ ["1", "2"], ["3"], ["4", "5"] ]
]

这个

[
  [1, "green", "1"],
  [1, "green", "2"],
  [1, "blue", "3"],
  [1, "black", "4"],
  [1, "black", "5"],
]

---

我试过了，但是运气不好。非常感谢您提供的任何帮助，当然我正在寻找性能解决方案。

我并不完全清楚模式，但这得到了您提供的示例的预期输出：

data[1].
  zip(data[2]).
  flat_map { |x, ys| [x].product(ys) }.
  map { |zs| [data[0], *zs] }
#=> [[1, "green", "1"], [1, "green", "2"], [1, "blue", "3"], 
#    [1, "black", "4"], [1, "black", "5"]]

我们被给予

arr = [1, ["green", "blue", "black"], [ ["1", "2"], ["3"], ["4", "5"] ]]

以下是获得所需结果的几种方法

#1

arr[1].flat_map.with_index { |color,i| [arr[0]].product([color], arr[2][i]) }
  #=> [[1, "green", "1"], [1, "green", "2"], [1, "blue", "3"],
  #    [1, "black", "4"], [1, "black", "5"]]

步骤如下

enum0 = arr[1].flat_map
  #=> #<Enumerator: ["green", "blue", "black"]:flat_map>
enum1 = enum0.with_index
  #=> #<Enumerator: #<Enumerator: ["green", "blue", "black"]:flat_map>:with_index>

b = arr[1].zip(arr[2])
  #=> [["green", ["1", "2"]], ["blue", ["3"]], ["black", ["4", "5"]]]

生成第一个值并传递给块，分配块变量并执行块计算

color, i = enum1.next
  #=> ["green", 0]
color
  #=> "green"
i #=> 0
[arr[0]].product([color], arr[2][i])
  #=> [1].product(["green"], )
  #=> [[1, "green", "1"], [1, "green", "2"]]

color, a = b[0]
  #=> ["green", ["1", "2"]]
color
  #=> "green"
a #=> ["1", "2"]
[arr[0]].product([color], a)
  #=> [["1"]].product(["green"], ["1", "2"])
  #=>  [[1, "green", "1"], [1, "green", "2"]]

由

enum1

生成的其余两个元素的计算结果类似

另一种方法是dup

arr[2]

并移动dup的元素：

a2 = arr[2].dup
arr[1].flat_map { |color,i| [arr[0]].product([color], a2.shift) }

#2

arr[1].zip(arr[2]).flat_map { |color, a| [arr[0]].product([color], a) }
  #=> [[1, "green", "1"], [1, "green", "2"], [1, "blue", "3"],
  #    [1, "black", "4"], [1, "black", "5"]]

步骤如下

enum0 = arr[1].flat_map
  #=> #<Enumerator: ["green", "blue", "black"]:flat_map>
enum1 = enum0.with_index
  #=> #<Enumerator: #<Enumerator: ["green", "blue", "black"]:flat_map>:with_index>

b = arr[1].zip(arr[2])
  #=> [["green", ["1", "2"]], ["blue", ["3"]], ["black", ["4", "5"]]]

b[0]

被传递到

flat\u map

，分配块变量并执行块计算

color, i = enum1.next
  #=> ["green", 0]
color
  #=> "green"
i #=> 0
[arr[0]].product([color], arr[2][i])
  #=> [1].product(["green"], )
  #=> [[1, "green", "1"], [1, "green", "2"]]

color, a = b[0]
  #=> ["green", ["1", "2"]]
color
  #=> "green"
a #=> ["1", "2"]
[arr[0]].product([color], a)
  #=> [["1"]].product(["green"], ["1", "2"])
  #=>  [[1, "green", "1"], [1, "green", "2"]]

---

将

b

的其余元素传递到

map

后，返回所需的数组。

与建议的解决方案相比，我需要一个更通用、更灵活的解决方案（我的缺点是，我应该更清楚要求），因此我提出了以下建议：

class Array
  def transpose_rows
    arys = self.select{|el| el.is_a?(Array)}
    if arys.size == 0
      [self]
    else 
      result = []
      (arys.map(&:size).max || 1).times.map{ |i|
        self.map { |r| 
          r.is_a?(Array) ? r[i] : r
        }.transpose_rows.map{|r| result << r}
      }
      result
    end
  end
end

[
  2, 
  [3,4,5], 
  6, 
  [7,8,9], 
  [ [11,22], [33], [44,55] ], 
  [0, 1, 2],
  [ [66], [77], [nil,99] ],
  4
].transpose_rows

# => [
#   [2, 3, 6, 7, 11, 0, 66, 4], 
#   [2, 3, 6, 7, 22, 0, nil, 4], 
#   [2, 4, 6, 8, 33, 1, 77, 4], 
#   [2, 5, 6, 9, 44, 2, nil, 4], 
#   [2, 5, 6, 9, 55, 2, 99, 4]
# ]

---

谢谢，托克兰。作为一个平面地图的信徒，我应该看到这一点。我编辑过。当你给出一个例子时，给每个输入对象分配一个变量是很有帮助的（例如，

arr=[1、[“绿色”、“蓝色”、“黑色”]、[[“1”、“2”]、[“3”]、[“4”、“5”]]]

。这样，读者就可以在答案和注释中引用变量，而无需定义它们，所有读者都将使用相同的变量名。