ruby-on-rails - Ruby group_by 具有不同键的哈希数组(键不固定)

Question

我想将散列数组分组为:

array = [{"value"=>[{"a"=>1},{"b"=>4}]},{"value"=>[{"c"=>4},{"d"=>3},{"a"=>3},{"b"=>54}]}]

到:

grouped_data = {"a"=>[1,3],"b"=>[4,54],"c"=>[4],"d"=>[3]}

我可以将数组转换为array#1 = [{"a"=>1}, {"b"=>4}, {"c"=>4}, {"d"=>3}, {"a"=> 3}, {"b"=>54}] 使用 array.map(&:values).flatten。我可以使用遍历所有数据将 array#1 转换为散列 grouped_data 的原样。但我需要一种更有效的方法，比如在动态键上使用 group_by(键不固定。)

如果键是固定的，我知道如何分组。我需要对动态更改的键进行 group_by。

Answer 1

我不希望为此赢得任何可读性奖项...

array.map(&:values)
     .flatten
     .group_by { |o| o.keys.first }
     .map { |key, v| [key, v.map(&:values).flatten] }
     .to_h
=> {"a"=>[1, 3], "b"=>[4, 54], "c"=>[4], "d"=>[3]}

如果有人好奇，我整理了一些粗略的基准:

require 'benchmark'

n = 10000
letters = ('a'...'z').to_a
numbers = (0...1000).to_a

built_array = []
n.times do |i|
  values = []
  obj_size = (1...letters.size).to_a.sample
  obj_size.times do |j|
    values << {
      "#{letters.sample}" => numbers.sample
    }
  end
  built_array << { "value" => values }
end

Benchmark.bm(15) do |x|
  x.report("anthony") { anthony(built_array) }
  x.report("eric each") { eric_each(built_array) }
  x.report("eric ewo") { eric_each_with_object(built_array) }
  x.report("eric merge") { eric_merge(built_array) }
  x.report("ed inject") { ed_inject(built_array) }
end

                      user     system      total        real
anthony           0.130000   0.010000   0.140000 (  0.146601)
eric each         0.060000   0.000000   0.060000 (  0.067160)
eric ewo          0.070000   0.000000   0.070000 (  0.076125)
eric merge       25.250000   0.880000  26.130000 ( 28.297592)
ed inject         0.080000   0.010000   0.090000 (  0.111045)