Mapping does not work in short style (.map(&:id))

Question

I try to perform this very simple RUBY map statement:

    result_apartments = [{:id=>"593363170", :title=>"Country House", :price=>{:cents=>30000000, :currency=>"EUR", :human=>"€300,000.00"}, :sqm=>130, :numberOfBedrooms=>30, :numberOfBathrooms=>1}, {:id=>"906270510", :title=>"City Flat", :price=>{:cents=>80000000, :currency=>"USD", :human=>"$800,000.00"}, :sqm=>60, :numberOfBedrooms=>5, :numberOfBathrooms=>23}]


puts result_apartments.map(&:id)

Somehow it throws the error: map': undefined method id' for #<Hash:0x0055d52

What is the issue here? What is wrong in the array presentation? And how should I change it so that I can map it in this short cut version: map(&:id)

Somehow (map{|a| a[:id]}) works!

Answer 1

the short method is attempting to call a method id on each hash. That's not a hash method. If you do...

result_apartments.first.id

You'll see that id isn't a valid method.

Instead of hashes you could have an array of OpenStruct

require 'ostruct'

structured_result_apartments = result_paraments.map { |hash| OpenStruct.new hash }

Then you can do

structured_result_apartments.map(&:id)