Access value from multidimensional Hash rails

Question

I have to access the id and other important information of each operator. The structure of given data is:

{:items=>
  [{:id=>"868f136b-ec4e-4794-a3a9-a70d4b83ab38",
    :clientId=>"e92ca89f-8524-451a-9346-666d6ff39329",
    :name=>"allergy_type_display",
    :description=>nil,
    :mnemonic=>"allergy_type_display",
    :columnType=>"dropdown",
    :entityId=>"d96804c4-c815-4d65-891f-b5e5c418587e",
    :createdAt=>"2019-11-27T05:01:34.000Z",
    :updatedAt=>"2019-11-27T05:01:34.000Z",
    :display=>true,
    :fallbackId=>nil,
    :conceptDisplay=>false,
    :businessName=>nil,
    :operators=>
     [{:id=>"15e8c619-7b5b-4612-b2e9-7a17112eceb9",
       :mnemonic=>"gte",
       :description=>"Greater than Equals to",
       :createdAt=>"2019-07-01T13:10:15.000Z",
       :updatedAt=>"2019-07-01T13:10:15.000Z",
       :clientId=>nil},
      {:id=>"38888bef-5442-4c72-b88e-44f4fd3e5614",
       :mnemonic=>"eq",
       :description=>"Equals To",
       :createdAt=>"2019-06-26T09:30:15.000Z",
       :updatedAt=>"2019-07-06T04:14:59.000Z",
       :clientId=>nil},
      {:id=>"4fd6ce17-10d3-42a3-8e4e-24773360db5d",
       :mnemonic=>"ne",
       :description=>"Not Equals To",
       :createdAt=>"2019-06-26T09:19:03.000Z",
       :updatedAt=>"2019-07-06T04:58:11.000Z",
       :clientId=>nil},
      {:id=>"b252eac5-f5dc-41ce-bc49-2364f5a73bb1",
       :mnemonic=>"lte",
       :description=>"Less than Equals to",
       :createdAt=>"2019-07-01T13:10:15.000Z",
       :updatedAt=>"2019-07-01T13:10:15.000Z",
       :clientId=>nil}]}]}

Here I am not able to access the id of each operator. All these values I have stored in instance variable @ans.

Answer 1

You can do this with dig and pluck methods

@ans.dig(:items, 0, :operators)&.pluck(:id)

Or if you don't use Rails

@ans.dig(:items, 0, :operators)&.map { |el| el[:id] }

Or if you use old ruby which doesn't support safe navigation and dig method, you can use try method:

@ans[:items].try(:[], 0).try(:[], :operators).try(:map) { |h| h[:id] }

# output

["15e8c619-7b5b-4612-b2e9-7a17112eceb9", "38888bef-5442-4c72-b88e-44f4fd3e5614", "4fd6ce17-10d3-42a3-8e4e-24773360db5d", "b252eac5-f5dc-41ce-bc49-2364f5a73bb1"]