问Rails:循环比较两个数组并将匹配推送到新数组
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Stack Overflow用户

提问于 2015-03-23 14:54:42

回答 2查看 1.3K关注 0票数 1

我有两个数组，我需要互相检查。当找到匹配时，我需要从第一个数组中取消值，并将该值推送到一个新数组。

下面是一个示例：

第一阵列import_data

["mario", "blue", "SGC", "CJ672PA0"], 
["solid snake", "green", "NID", "VI6965KD"], 
["samus", "maroon", "TRUST", "DNYU6539"], 
["deckard cain", "purple", "JAFA", "SJW252MZ"],
["wedge", "yellow", "WALTER", "UJ28NVM1"]

第二阵列current_data

["gordon", "orange", "DRONE", "OGJR8C0D"], 
["samus", "black", "TRUST", "DNYU6539"], 
["commander shepard", "red", "WHX", "TH985OI3"]

请注意，"samus“显示在两个数组中，所有数据都相同，但颜色发生了更改。

我的意图是循环遍历import_data，检查数组中每个项的最后一个索引(8位数字的"id")，并将其与current_data进行比较。每次找到“匹配”(基于8位数字的"id")时，我都希望将该项推入一个新的数组update_data中，然后在import_data数组中进行匹配的unset。

问题是两个数组的长度不同。因此，一旦我的循环超过一项的长度，它就不能再检查该索引，从而导致错误。

我的代码本质上是这样的：

import_data.each_with_index do |data, index|
  if data[3] == current_data[index].id
    # @update_data << somehow push all of the data
  end
end

之所以不能工作，是因为import_data的长度比current_data的长。这将导致错误：

“未定义的方法‘`id’for nil:NilClass"

理想情况下，最终结果如下：

"samus“已从import_data数组中移除并推送到update_data数组中。

import_data阵列一个又一个循环

["mario", "blue", "SGC", "CJ672PA0"], 
["solid snake", "green", "NID", "VI6965KD"], 
--- 
["deckard cain", "purple", "JAFA", "SJW252MZ"],
["wedge", "yellow", "WALTER", "UJ28NVM1"]

新填充数组update_data

 ["samus", "maroon", "TRUST", "DNYU6539"]

ruby

arrays

comparison

ruby-on-rails

回答 2

Stack Overflow用户

回答已采纳

发布于 2015-03-23 18:32:00

由于普拉卡什的答案是可行的，我认为这是比较直接的：

import_data = [
  ["mario", "blue", "SGC", "CJ672PA0"], 
  ["solid snake", "green", "NID", "VI6965KD"], 
  ["samus", "maroon", "TRUST", "DNYU6539"], 
  ["deckard cain", "purple", "JAFA", "SJW252MZ"],
  ["wedge", "yellow", "WALTER", "UJ28NVM1"]
]
current_data = [
  ["gordon", "orange", "DRONE", "OGJR8C0D"], 
  ["samus", "black", "TRUST", "DNYU6539"], 
  ["commander shepard", "red", "WHX", "TH985OI3"]
]

current_ids = current_data.map {|c| c[3]}

update_data = import_data.inject([]) do |result, data|
  result << import_data.delete(data) if current_ids.include?(data[3])
  result
end

跑完之后你会得到：

update_data = [
  ["samus", "maroon", "TRUST", "DNYU6539"]
]
import_data = [
  ["mario", "blue", "SGC", "CJ672PA0"], 
  ["solid snake", "green", "NID", "VI6965KD"], 
  ["deckard cain", "purple", "JAFA", "SJW252MZ"],
  ["wedge", "yellow", "WALTER", "UJ28NVM1"]
]

希望能帮上忙。

票数 3

Stack Overflow用户

发布于 2015-03-23 15:38:08

完成你正在做的事情的一种方法：

import_data = [ 
                ["mario", "blue", "SGC", "CJ672PA0"], 
                ["solid snake", "green", "NID", "VI6965KD"], 
                ["samus", "maroon", "TRUST", "DNYU6539"], 
                ["deckard cain", "purple", "JAFA", "SJW252MZ"],
                ["wedge", "yellow", "WALTER", "UJ28NVM1"]
              ]

current_data = [
                 ["gordon", "orange", "DRONE", "OGJR8C0D"], 
                 ["samus", "black", "TRUST", "DNYU6539"], 
                 ["commander shepard", "red", "WHX", "TH985OI3"]
                ]

查找这两个数组的键：

import_data_keys = import_data.map { |x| x[3] }
=> ["CJ672PA0", "VI6965KD", "DNYU6539", "SJW252MZ", "UJ28NVM1"]
current_data_keys = current_data.map { |x| x[3] }
=> ["OGJR8C0D", "DNYU6539", "TH985OI3"]

通过将这两个数组相交来查找公共密钥：

common_keys = import_data_keys & current_data_keys
=> ["DNYU6539"]

使用common_keys从import_data中删除并推送到update_data。

common_keys.each do |key|
  import_data.each_with_index do |data, index|
    if data[3] == key
      update_data << import_data[index]
      import_data.delete_at(index)
      break
    end
  end
end