Ruby on rails rails：一种更有效的对象关系数组映射新数组的方法

数组A基本上是一个关系散列，我想取出所有匹配的num或alpha来创建一个单独的数组，即B和C

所以一旦我有了B数组，我就可以立即知道alpha'a'的num:1和2与 C、 我可以立即知道num'1'有alpha a和b

 A = [{ alpha: 'a', num: '1'},
      { alpha: 'b', num: '1'},
      { alpha: 'a', num: '2'},
      { alpha: 'b', num: '2'}]

 B = [{alpha: 'a', num: [1, 2]},
      {alpha: 'b', num: [1, 2]}]

 C = [{num: '1', alpha: [a, b]},
      {num: '2', alpha: [a, b]}]

到目前为止，我有以下几点，但我认为必须有一种更简单、更有效的方法来做到这一点

B = []
C = []

A.each do |datum|
    if !B.any?{|value| value.alpha == datum.alpha}
      temp = {
          alpha: datum.alpha,
          num: (A.map {|value| (value.num == datum.num)? value.num : nil }).compact
      }

      B << temp
    end

    if !C.any?{|value| value.num == datum.num}
      temp = {
          num: datum.num,
          alpha: (A.map {|value| (value.alpha == datum.alpha)? value.alpha : nil }).compact
      }

      C << temp
    end
  end

B=[]
C=[]
A.每个do |基准|
如果！B.any？{| value | value.alpha==datum.alpha}
温度={
alpha:datum.alpha，
num：（A.map{| value |（value.num==datum.num）？value.num:nil}）.compact
}
B以下是技巧：

a = [
      { alpha: 'a', num: '1'},
      { alpha: 'b', num: '1'},
      { alpha: 'a', num: '2'},
      { alpha: 'b', num: '2'}
    ]

alpha_arry = a.group_by { |h| h[:alpha] }.map do |key,value| 
  {:alpha => key, :num => value.collect { |num_hash| num_hash[:num] }} 
end
alpha_arry
# => [{:alpha=>"a", :num=>["1", "2"]}, {:alpha=>"b", :num=>["1", "2"]}]
num_arry = a.group_by { |h| h[:num] }.map do |key,value| 
  {:num => key, :alpha => value.collect { |alpha_hash| alpha_hash[:alpha] }} 
end
num_arry
# => [{:num=>"1", :alpha=>["a", "b"]}, {:num=>"2", :alpha=>["a", "b"]}]