constructing a new hash from the given values

问题

I seem lost trying to achieve the following, I tried all day please help

I HAVE

h = {
    "kv1001"=> {
      "impressions"=>{"b"=>0.245, "a"=>0.754},
      "visitors"   =>{"b"=>0.288, "a"=>0.711},
      "ctr"        =>{"b"=>0.003, "a"=>0.003},
      "inScreen"=>{"b"=>3.95, "a"=>5.031}
    },
    "kv1002"=> {
      "impressions"=>{"c"=>0.930, "d"=>0.035, "a"=>0.004, "b"=>0.019,"e"=>0.010},
      "visitors"=>{"c"=>0.905, "d"=>0.048, "a"=>0.005, "b"=>0.026, "e"=>0.013},
      "ctr"=>{"c"=>0.003, "d"=>0.006, "a"=>0.004, "b"=>0.003, "e"=>0.005},
      "inScreen"=>{"c"=>4.731, "d"=>4.691, "a"=>5.533, "b"=>6.025, "e"=>5.546}
    }
}

MY GOAL

{
    "segment"=>"kv1001=a",
    "impressions"=>"0.754",
    "visitors"=>"0.711", 
    "inScreen"=>"5.031",
    "ctr"=>"0.003"
}, {
    "segment"=>"kv1001=b", 
    "impressions"=>"0.245", 
    "visitors"=>"0.288", 
    "inScreen"=>"3.95",
    "ctr"=>"0.003"
}, {
    "segment"=>"kv1002=a", 
    "impressions"=>"0.004" 
    #... etc
}

My goal is to create a hash with 'kv1001=a' i.e the letters inside the hash and assign the keys like impressions, visitors etc. The example MY GOAL has the format So format type "kv1001=a" must be constructed from the hash itself, a is the letter inside the hash.

I have solved this now

`data_final = []
h.each do |group,val|
  a = Array.new(26){{}}
  val.values.each_with_index do |v, i|
    keys = val.keys
    segment_count = v.keys.length
    (0..segment_count-1).each do |n|
      a0 = {"segment" => "#{group}=#{v.to_a[n][0]}", keys[i] => v.to_a[n][1]}
      a[n].merge! a0
      if a[n].count > 4
        data_final << a[n]
      end
    end
  end
end`

回答1:

Here's a simpler version

h.flat_map do |segment, attrs| 
  letters = attrs.values.flat_map(&:keys).uniq
  # create a segment entry for each unique letter
  letters.map do |letter|
    seg = {"segment" => "#{segment}=#{letter}"}
    seg.merge Hash[attrs.keys.map {|key| [key,attrs[key][letter]]}]
  end
end

Output:

[{"segment"=>"kv1001=b",
  "impressions"=>0.245,
  "visitors"=>0.288,
  "ctr"=>0.003,
  "inScreen"=>3.95},
 {"segment"=>"kv1001=a",
  "impressions"=>0.754,
  "visitors"=>0.711,
  "ctr"=>0.003,
  "inScreen"=>5.031},
 {"segment"=>"kv1002=c",
  "impressions"=>0.93,
  "visitors"=>0.905,
  "ctr"=>0.003,
  "inScreen"=>4.731},
 {"segment"=>"kv1002=d",
  "impressions"=>0.035,
  "visitors"=>0.048,
  "ctr"=>0.006,
  "inScreen"=>4.691},
 {"segment"=>"kv1002=a",
  "impressions"=>0.004,
  "visitors"=>0.005,
  "ctr"=>0.004,
  "inScreen"=>5.533},
 {"segment"=>"kv1002=b",
  "impressions"=>0.019,
  "visitors"=>0.026,
  "ctr"=>0.003,
  "inScreen"=>6.025},
 {"segment"=>"kv1002=e",
  "impressions"=>0.01,
  "visitors"=>0.013,
  "ctr"=>0.005,
  "inScreen"=>5.546}]

来源：https://stackoverflow.com/questions/25186259/constructing-a-new-hash-from-the-given-values

标签

ruby-on-rails

ruby

data-structures

hash