如何有效地從json列表中接收紅寶石哈希

Question

我正在試圖使頁面中的內容是來自兩個數組的數據。 我有兩個列表（陣列）與哈希：

arr1 = [ 
     { "device"=>100, "phone"=>"12345" }, 
     ..., 
     { "device"=>102, "phone"=>"12346" } 
     ] 


arr2 = [ 
     { "device"=>100, "type"=>"mobile", "name"=>"nokia" }, 
     ..., 
     { "device"=>102, "type"=>"VIOP", "name"=>"smth" } 
     ] 

How can I join hashes from arr1 and arr2 by "device" to get a result array:

result = [ { "device"=>100, "phone"=>"12345", "type"=>"mobile", "name"=>"nokia" }, ..., { "device"=>102, "phone"=>"12346", "type"=>"VIOP", "name"=>"smth" } ] 

頁，其中包括表結果數組，負荷非常緩慢，我需要找到產生result_array的最快方式。

請幫助我。

Answer 1

這會工作：

(arr1 + arr2).group_by { |i| i["device"] }.map { |d,(i1,i2)| i1.merge(i2)} 
#=> [{"device"=>100, "phone"=>"12345", "type"=>"mobile", "name"=>"nokia"}, {"device"=>102, "phone"=>"12346", "type"=>"VIOP", "name"=>"smth"}] 

Answer 2

也許這不是最漂亮的一個，但它的工作原理：

result = arr1.collect{|a| h = arr2.select{|b| b["device"] == 
a["device"]}.first; h ? a.merge(h) : a } 

你需要的東西更快對於大數據量的？

h = Hash.new 
arr1.each do |a| 
    h[ a["device" ] ] ||= Hash.new 
    h[ a["device" ] ].merge!(a) 
end 
arr2.each do |a| 
    h[ a["device" ] ] ||= Hash.new 
    h[ a["device" ] ].merge!(a) 
end 
result = h.values 

Answer 3

多種方法來解決它。這裏是一個非常可讀的方式做到這一點：

# prepare an index hash for easier access of data by device 
first_by_device = arr1.group_by {|a| a['device'] } 

# build a new array joining both data hashes for each item 
result = arr2.map do |item| 
    device = item['device'] 
    item.merge first_by_device(device) 
end 

Answer 4

(arr1 + arr2).group_by { |i| i["device"] }.values.map{|x|x.reduce(&:merge)}