如何在 rails 中将数组对象转换为散列

Question

我有一个哈希数组对象：

{
  false=>[#<Campaign id: 1, name: "campaign 1", active: false>, #<Campaign id: 3, name: "campaign 3", active: false>, #<Campaign id: 4, name: "campaign 4", active: false>], 
  true=>[#<Campaign id: 2, name: "campaign 2", active: true>]
} 

如何将上面的散列转换为散列

{
  false=>[{id:1, name:"campaign 1"}, {id:3, name: "capaign 3"}, ....],
  true =>[{id:2, name:"campaign 2"}]
}

Answer 1

hash.each {|k,v| hash[k] = v.map{|e| {id: e[:id], name: e[:name]}}}

并且如果你可以使用select_all方法得到散列数组，而不是对象数组，那么你不需要将对象隐藏到散列。

ModelName.connection.select_all("select id, name from <table_name>;")
=> [{id:xxx, name: xxx}.......]

Answer 2

在你的对象上使用 attributes 方法

attributes() public

Returns a hash of all the attributes with their names as keys and the values of the attributes as values.

hash = {
  false => [#<Campaign id: 1, name: "campaign 1", active: false>, #<Campaign id: 3, name: "campaign 3", active: false>, #<Campaign id: 4, name: "campaign 4", active: false>], 
  true  => [#<Campaign id: 2, name: "campaign 2", active: true>]
} 

所以这一行应该可以解决问题 -

hash.each {|k, v| hash[k] = v.map(&:attributes) }

{
  false => [{"id": 1, "name": "campaign 1", "active": false}, {"id": 3, "name": "campaign 3", "active": false}, {"id": 4, "name": "campaign 4", "active": false}], 
  true  => [{"id": 2, "name": "campaign 2", "active": true}]
}