从两个数据源创建哈希的最优雅方式

Question

我有 building_table 和 api::building_table，我想默认使用 building_table 中的数据，但如果 building_table 中不存在这些数据我想在 api::building_table 获得它。问题是有些属性可能不存在于 building_table 中，但存在于 api building_table 中。每个 table.

中也有不同名称的列

这是我的示例代码

def get_building_info
  building = Building.find_by(id: params[:id])
  api_building = Api::Building.find_by(id: params[:id])
  building_hash = {}
  building_hash[:name] = building.name || api_building.name
  building_hash[:room] = building.room || api_building.room
  building_hash[:rent] = building.rent || api_building.monthly_fee
...
end

有没有更优雅的方式来做到这一点？顺便说一句，这是在我的控制器中。

Answer 1

可能存在许多解决方案来实现这一点，但是，这里有一个更简单的解决方案：

def get_building_info
  building = Hash.new
  building[:name], building[:room] = desired_building.name, desired_building.room 
end

private

 def desired_building
    Building.find_by(id: params[:id]) || 
    Api::Building.find_by(id: params[:id])
 end

Answer 2

我认为您的做法是正确的，但是 building 变量将被覆盖，您需要定义一个新变量，例如 building2 = {}

Answer 3

before_action :find_records, only: :get_building_info

def get_building_info
  building_hash = {}
  building_hash[:name] = building_name
  building_hash[:room] = building_room
  # OR
  building_hash[:name], building_hash[:room] = building_name, building_room

end

private

def find_records
  @building = Building.find_by(id: params[:id])
  @api_building = Api::Building.find_by(id: params[:id])
end

def building_name
  @building.name || @api_building.name
end

def building_room
  @building.room || @api_building.room
end

Answer 4

通用方法，接受键列表作为参数：

def get_building_info(keys = %i[name room rent].zip(%i[name room fee]))
  building = Building.find_by(id: params[:id])
  api_building = Api::Building.find_by(id: params[:id])
  keys.map do |key, api_key|
    [
      key,
      building.attributes[key.to_s] || api_building.attributes[api_key.to_s]
    ]
  end.to_h
end

Answer 5

你可以使用 Enumerable#each_with_object:

attrs = [ %i[name name], %i[room room], %i[rent monthly_fee] ]
attrs.each_with_object({}) do |(name, alias_name), h|
  h[name] = building[name] || api_building[alias_name]
end

从两个数据源创建哈希的最优雅方式

Most elegant way to create hash from two datasource

ruby

ruby-on-rails

ruby-on-rails-4