Insert new key value into nested hash in Ruby

Question

I am trying to insert a new key/value { type: 'Profile'} into the photo hash that has id = 111.

photo_hash = [{"id": "111","photo": "http://photo.com/111.jpeg"}, {"id": "222",  "photo": "http://photo.com/222.jpeg"}] 

So the final result should look like:

photo_hash = [{"id": "111","photo": "http://photo.com/111.jpeg", "type" : "Profile"}, {"id": "222",  "photo": "http://photo.com/222.jpeg"}] 

I feel like this should be pretty straight forward in Ruby but I am very stuck

Answer 1

The question suggests to me that the element h (a hash) of photos for which h[:id] = "111 (if there is one), is to be modified in place by adding the key-value pair :type=>"Profile" .

photos = [{"id": "111", "photo": "http://photo.com/111.jpeg"},
          {"id": "222", "photo": "http://photo.com/222.jpeg"}]

insert_item = { "type": "Profile" }

h = photos.find { |h| h[:id] == "111" }
h.update(insert_item) unless h.nil?
photos
  #=> [{:id=>"111", :photo=>"http://photo.com/111.jpeg", :type=>"Profile"},
  #    {:id=>"222", :photo=>"http://photo.com/222.jpeg"}]

See Hash#update (aka merge! ).

Answer 2

You need to construct a new array from your existing:

photos = [{"id": "111","photo": "http://photo.com/111.jpeg"}, {"id": "222",  "photo": "http://photo.com/222.jpeg"}]

new_photos = photos.map do |photo|
  if photo[:id] == '111'
    photo.merge(type: 'Profile')
  else
    photo
  end
end

Answer 3

You rly dont need to find object or create new Array . Hash it self its object and can be updated.

photos = [{"id": "111","photo": "http://photo.com/111.jpeg"}, {"id": "222",  "photo": "http://photo.com/222.jpeg"}]
photos.each do |hsh|
  if hsh[:id] == '111'
    hsh[:type] = 'Profile'
    break
  end
end
photos
# => [{:id=>"111", :photo=>"http://photo.com/111.jpeg", :type=>"Profile"}, {:id=>"222", :photo=>"http://photo.com/222.jpeg"}]

Answer 4

If you need to update multiple values from different objects with different ids you could also build a lookup tree. (Assuming there are no duplicate ids.)

photos = [{"id": "111","photo": "http://photo.com/111.jpeg"}, {"id": "222",  "photo": "http://photo.com/222.jpeg"}]
photo_lookup = photos.map { |photo| [photo[:id], photo] }.to_h
#=> { 
#   "111" => {"id": "111","photo": "http://photo.com/111.jpeg"},
#   "222" => {"id": "222",  "photo": "http://photo.com/222.jpeg"}
# }

Then simply fetch the photo and update the value.

photo = photo_lookup["111"] and photo.update(type: 'Profile')
#                            ^ only update photo if it is found

This solution mutates the hash, meaning the hash in photos should also be updated.