Question

我现在有一个JSON字符串：

[{"id":1,"name":"good","created_at":"2014-07-28T19:45:50.440Z","updated_at":"2014-07-28T19:45:50.440Z"},{"id":2,"name":"better","created_at":"2014-07-28T19:45:50.447Z","updated_at":"2014-07-28T19:45:50.447Z"},{"id":3,"name":"best","created_at":"2014-07-28T19:45:50.449Z","updated_at":"2014-07-28T19:45:50.449Z"}]

我有一个阵列：

id = ["1", "3"]

我想检查公共ID并打印相关名称。对于上面的例子，我希望我的输出是：

 ["good","best"]

我希望输出最好是一个数组。有一个简单的方法来做到这一点？我一直在编写太多代码来完成这项工作并认为它应该很容易完成。有什么建议吗？

Answer 1

# initiate json string
json = %q([{"id":1,"name":"good","created_at":"2014-07-28T19:45:50.440Z","updated_at":"2014-07-28T19:45:50.440Z"},{"id":2,"name":"better","created_at":"2014-07-28T19:45:50.447Z","updated_at":"2014-07-28T19:45:50.447Z"},{"id":3,"name":"best","created_at":"2014-07-28T19:45:50.449Z","updated_at":"2014-07-28T19:45:50.449Z"}])

ids = ["1", "3"]

JSON.parse(json).select{|x| ids.include? x["id"].to_s}.map{|x| x["name"]}
#=> ["good", "best"]

Answer 2

require 'json'

def pluck(json, ids)
  json_parsed = JSON.parse(json)

  json_parsed.select do |obj|
    ids.include?(obj['id'])
  end
  .map do |obj|
    obj['name']
  end
end

# usage
json = '[{"id":1,"name":"good","created_at":"2014-07-28T19:45:50.440Z","updated_at":"2014-07-28T19:45:50.440Z"},{"id":2,"name":"better","created_at":"2014-07-28T19:45:50.447Z","updated_at":"2014-07-28T19:45:50.447Z"},{"id":3,"name":"best","created_at":"2014-07-28T19:45:50.449Z","updated_at":"2014-07-28T19:45:50.449Z"}]'
ids = [1, 3]
pluck(json, ids)

Answer 3

你控制器中的

可以这样做：

def  method_name

  render json: Model.pluck(:name).to_json

end

在Ruby中获取JSON和数组之间的公共元素

3 个答案: