ruby db结果集到散列中的数组

Question

我有一个数据库查询，它返回如下结果:

db_result.each {|row| puts row}
{"IP"=>"1.2.3.4","Field1"=>"abc","Field2"=>"123"}
{"IP"=>"1.2.3.4","Field1"=>"abc","Field2"=>"234"}
{"IP"=>"1.2.3.4","Field1"=>"bcd","Field2"=>"345"}
{"IP"=>"3.4.5.6","Field1"=>"bcd","Field2"=>"456"}
{"IP"=>"3.4.5.6","Field1"=>"bcd","Field2"=>"567"}

并希望将其放入哈希中，例如:

{
  "1.2.3.4" => {
    "abc" => ["123", "234"],
    "bcd" => "345"
  },
  "3.4.5.6" => {
    "bcd" => ["456", "567"]
  }
}

我目前正在做的是:

result_hash = Hash.new { |h, k| h[k] = {} }
db_result.each do |row|
  result_hash[row["IP"]] = Hash.new { |h, k| h[k] = [] } unless result_hash.has_key? row["IP"]
  result_hash[row["IP"]][row["Field1"]] <<  row["Field2"]
end 

哪个有效，但是想知道是否有更简洁的方法。

Answer 1

将此视为同行评审。作为处理和维护的建议...

我建议您希望数据结构更加一致。

而不是:

{
  "1.2.3.4" => {
    "abc" => ["123", "234"],
    "bcd" => "345"
  },
  "3.4.5.6" => {
    "bcd" => ["456", "567"]
  }
}

我建议:

{
  "1.2.3.4" => {
    "abc" => ["123", "234"],
    "bcd" => ["345"]
  },
  "3.4.5.6" => {
    "abc" => [],
    "bcd" => ["456", "567"]
  }
}

在每个子哈希中保留相同的键，并使值全部为数组。用于处理整个哈希的代码将更加简单且易于理解。