Move object to a parent object in ruby - arrays

Question

I have an array of objects like this:
[
{
"id": 2,
"title": "LA COPA",
"parent_menu_id": nil
},
{
"id": 3,
"title": "CALENDARIO",
"parent_menu_id": nil
},
{
"id": 5,
"title": "Torneo",
"parent_menu_id": 2
},
{
"id": 6,
"title": "Nice",
"parent_menu_id": 2
}
]
This is the structure of a menu.
Each object is an menu item.
If the key "parent_menu_id" is nil, it means that the item is a parent menu.
If it has a value, is a children. I.E the third item means that item id: 5 is child of item id:2.
This is the desired output:
[
{
"id": 2,
"title": "LA COPA",
"active": true,
"parent_menu_id": nil,
"submenus":[
{
"id": 5,
"title": "Torneo",
"active": true,
"parent_menu_id": 2
},
{
"id": 6,
"title": "Nice",
"parent_menu_id": 2
}
]
},
{
"id": 3,
"title": "CALENDARIO",
"active": true,
"parent_menu_id": nil
}
]
I know the algorithm:
if pareny_menu_id is different than nill search the key id == parent_menu_id
If submenu key is not present, create it.
Move the child item to the parent.
Then delete the child item from base location.
But I am not sure about the methods to use..
Any ideas?
Cheers!

Answer 1

#!ruby
require 'pp'
objects = [
{
"id" => 2,
"title" => "LA COPA",
"parent_menu_id" => nil
},
{
"id" => 3,
"title" => "CALENDARIO",
"parent_menu_id" => nil
},
{
"id" => 5,
"title" => "Torneo",
"parent_menu_id" => 2
},
{
"id" => 6,
"title" => "Nice",
"parent_menu_id" => 2
}
]
objects.collect! do |child|
if not child["parent_menu_id"].nil? then
parents = objects.select{|o| o["id"] == child["parent_menu_id"]}
parents.each do |pr|
pr["submenus"] ||= []
pr["submenus"] << child
end
end
child
end.select!{|o| o["parent_menu_id"].nil? }
pp objects
output:
[{"id"=>2,
"title"=>"LA COPA",
"parent_menu_id"=>nil,
"submenus"=>
[{"id"=>5, "title"=>"Torneo", "parent_menu_id"=>2},
{"id"=>6, "title"=>"Nice", "parent_menu_id"=>2}]},
{"id"=>3, "title"=>"CALENDARIO", "parent_menu_id"=>nil}]

Answer 2

arr = [
{
id: 2,
title: "LA COPA",
parent_menu_id: nil
},
{
id: 3,
title: "CALENDARIO",
parent_menu_id: nil
},
{
id: 5,
title: "Torneo",
parent_menu_id: 2
},
{
id: 6,
title: "Nice",
parent_menu_id: 2
}
]
parents, children = arr.partition { |g| g[:parent_menu_id].nil? }
#= [[{:id=>2, :title=>"LA COPA", :parent_menu_id=>nil},
# {:id=>3, :title=>"CALENDARIO", :parent_menu_id=>nil}],
# [{:id=>5, :title=>"Torneo", :parent_menu_id=>2},
# {:id=>6, :title=>"Nice", :parent_menu_id=>2}]]
children.each do |child|
parent_id = child[:parent_menu_id]
parent = parents.find { |p| p[:id] == parent_id }
if parent.key?(:submenus)
parent[:submenus] << child
else
parent[:submenus] = [child.merge(active: true)]
end
end
parents
#=> [{:id=>2, :title=>"LA COPA", :parent_menu_id=>nil,
# :submenus=>[{:id=>5, :title=>"Torneo", :parent_menu_id=>2, :active=>true},
# {:id=>6, :title=>"Nice", :parent_menu_id=>2}]},
# {:id=>3, :title=>"CALENDARIO", :parent_menu_id=>nil}]
Notes:
"id": 2 is redundant. Just use id: 2. You only need quotes when the symbol is comprised of more than one word.
I assumed that the key value pair active: true is only present for the first element of the value (array) of :submenus.