How to take keep parts of an array and form a new array? - ruby-on-rails

Question

I am building a Rails 5 app.
In this app I have connected to the Google Calendar API.
The connection works fine and I get a list of calendars back.
What I need to do is to get the Id and Summary of this JSON object that I get back from Google.
This is what I get
[{
"kind": "calendar#calendarListEntry",
"etag": "\"1483552200690000\"",
"id": "xxx.com_asae#group.calendar.google.com",
"summary": "My office calendar",
"description": "For office meeting",
"location": "344 Common st",
"colorId": "8",
"backgroundColor": "#16a765",
"foregroundColor": "#000000",
"accessRole": "owner",
"defaultReminders": [],
"conferenceProperties": {
"allowedConferenceSolutionTypes": [
"hangoutsMeet"
]
}
},
{
"kind": "calendar#calendarListEntry",
"etag": "\"1483552200690000\"",
"id": "xxx.com_asae#group.calendar.google.com",
"summary": "My office calendar",
"description": "For office meeting",
"location": "344 Common st",
"colorId": "8",
"backgroundColor": "#16a765",
"foregroundColor": "#000000",
"accessRole": "owner",
"defaultReminders": [],
"conferenceProperties": {
"allowedConferenceSolutionTypes": [
"hangoutsMeet"
]
}
}]
This is what I want to end up with
[{
"id": "xxx.com_asae#group.calendar.google.com",
"title": "My office calendar",
}]
The purpose of this is that I want to populate a selectbox using Selectize plugin

Answer 1

Another way to achieve removing of certain keys in your hash is by using Hash#reject method:
response = { your_json_response }
expected = [response[0].reject {|k| k != :id && k != :summary}]
The original response remains unchanged while a mutated copy of the original response is returned.

Answer 2

You can filter the desierd keys with the select method:
responde = {your_json_response}
expected = [response[0].select{|k,v| ['id','title'].include?(k)}]
response[0] retrieves the hash, and the select compares each key with the ones you want and returns a hash with only those key: value pairs.
EDIT: I missed that you don't have a "title" key on the original response, I would do this then:
response = {your_json_response}
h = response[0]
expected = [{'id' => h['id'], 'title' => h['summary']}]
EDIT 2: Sorry, the first example was not clear that there would be multiple hashes
expected = response.map{|h| {'id' => h['id'], 'title' => h['summary']}}
map iterates over each element of response and returns the result of the block applied for each iteration as an array, so the blocks is apllied to each h and it generates a new hash from it

Answer 3

I suggest this approach.
expected = response.each { |h| h.keep_if { |k, _| k == :id || k == :summary } }
It returns just the required pairs:
# => [{:id=>"xxx.com_asae#group.calendar.google.com", :summary=>"My office calendar"}, {:id=>"xxx.com_asae#group.calendar.google.com", :summary=>"My office calendar"}]
To remove duplicates, just do expected.uniq
If you need to change the key name :summary to :title do:
expected = expected.each { |h| h[:title] = h.delete(:summary) }
One liner
expected = response.each { |h| h.keep_if { |k, _| k == :id || k == :summary } }.each { |h| h[:title] = h.delete(:summary) }.uniq
Of course, maybe it is better to move .uniq as first method expected = response.uniq.each { .....