Ruby更改哈希的键值答案

【问题标题】：Ruby change key value of hashRuby更改哈希的键值
【发布时间】：2021-12-07 12:03:02
【问题描述】：

我有一个返回这个数组和哈希的查询。如何更改哈希并向其添加新的键值对 import_id: 1, cost: 0 或者我可以在查询中执行 map 吗？

查询

name = Store.joins(:paid => :supply).group(:name).select("supply.name").where("stores.identifier IN (?) ", tids).pluck(:supply_id, :name)

数组

[[258, "Square"], [245, "App"]]

当我将其转换为哈希时，它会返回

{258=>"Square", 245=>"App"}

想要的输出

{{supply_id: 258, name: "Square", import_id: 1, cost: 0}, {supply_id: 245, name: "App", import_id: 1, cost: 0}}

【问题讨论】：

标签： arrays ruby-on-rails ruby hash

【解决方案1】：

看起来响应是[supply_id, name] 对的数组。您可以使用适当的符号键轻松解构数组并将数据重组为哈希。

array = [[258, "Square"], [245, "App"]]

array.map do |(id, name)|
  { supply_id: id, name: name, import_id: 1, cost: 0 }
end

# [{:supply_id=>258, :name=>"Square", :import_id=>1, :cost=>0}, ...]

【讨论】：

【解决方案2】：

使用#select 代替#pluck 并调用.as_json 或.map(&:attributes)

Store.joins(:paid => :supply).group(:name)
  .select("supply.name").where("stores.identifier IN (?) ", tids)
  .select(:supply_id, :name).as_json

# [{supply_id: 258, name: "Square"}, {supply_id: 245, name: "App"}]

或

Store.joins(:paid => :supply).group(:name)
  .select("supply.name").where("stores.identifier IN (?) ", tids)
  .select(:supply_id, :name).map(&:attributes)

# [{supply_id: 258, name: "Square"}, {supply_id: 245, name: "App"}]

或者你可以构造带有{import_id: 1, cost: 0}的哈希

Store.joins(:paid => :supply).group(:name)
  .select("supply.name").where("stores.identifier IN (?) ", tids)
  .select(:supply_id, :name)
  .map {|e| {supply_id: e.supply_id, name: e.name, import_id: 1, cost: 0} }

# [{supply_id: 258, name: "Square", import_id: 1, cost: 0}, {supply_id: 245, name: "App", import_id: 1, cost: 0}]

或

您可以在哈希生成步骤中使用Hash#merge 来包含{import_id: 1, cost: 0}

hash.merge({import_id: 1, cost: 0})

# To achieve: {{supply_id: 258, name: "Square", import_id: 1, cost: 0}, {supply_id: 245, name: "App", import_id: 1, cost: 0}}

【讨论】：