Rails: Values not getting assigned to array when in a do loop

Question

I have an array called components

components = [
   {
      :name => "Component 1",
      :order => "1"
   },
   {
      :name => "Component 2",
      :order => "2"
   },
   {
      :name => "Component 3",
      :order => "3"
   },
   {
      :name => "Component 4",
      :order => "4"
   }
]

And another array called subcomponent

subcomponents = [
   {
      :name => "Subcomponent 1A",
      :order => "1A"
   },
   {
      :name => "Subomponent 1B",
      :order => "1B"
   },
   {
      :name => "Component 2A",
      :order => "2A"
    },
   {
      :name => "Component 4A",
      :order => "4A"
   }
]

I'm trying to get it so that the subcomponents appear underneath a component object if they are a subcomponent of that object. This is the expected output:

components = [
   {
      :name => "Component 1",
      :order => "1",
      :subcomponents => [
         {
            :name => "Subcomponent 1A",
            :order => "1A"
         },
         {
            :name => "Subomponent 1B",
            :order => "1B"
         }
      ]
   },
   {
      :name => "Component 2",
      :order => "2",
      :subcomponents => [ 
         {
            :name => "Component 2A",
            :order => "2A"
         }
      ]
   },
   {
      :name => "Component 3",
      :order => "3",
      :subcomponent => []
   },
   {
      :name => "Component 4",
      :order => "4",
      :subcomponent => [
         {
            :name => "Component 4A",
            :order => "4A"
         }
      ]
   }
]

I've created a loop to try to do this:

components.each do |c|
      c.class.module_eval { attr_accessor :subcomponents}
      c.subcomponents = []

      subcomponents.each do |s|
        if /#{c["order"]}[A-Z]/ =~ s["order"]
          #This is never assigned but it does make it into this statement 
          c.subcomponents << s
        end
      end 

     puts c.subcomponents.to_s # This prints []
end

As I've put in my code comments, the subcomponent is never assigned back to the component.subcomponents arrays even though the if statement is stepped into.

Am I missing something where the scope of component.subcomponents isn't accessible anymore or is at a different scope?

What should I be doing to ensure I can assign value component.subcomponents?

gtournie · Accepted Answer · 2017-08-17 17:39:31Z

1

components.each do |c|
  c[:subcomponents] = []
  subcomponents.each do |s|
    c[:subcomponents] << s if /#{c[:order]}[A-Z]/ =~ s[:order]
  end 
end

answered Aug 17, 2017 at 17:39

gtournie

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Comments

Lwin Htoo Ko · Accepted Answer · 2017-08-17 17:28:40Z

0

Hope this work.

components.each do |component|
  component[:subcomponents] = []
end

subcomponents.each do |subcomponent|
  order = subcomponent[:order][/\d+/]

  components.each do |component|
    if order == component[:order]
      component[:subcomponents] << subcomponent
    end
  end
end

answered Aug 17, 2017 at 17:28

Lwin Htoo Ko

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Comments

Vijay Agrawal · Accepted Answer · 2017-08-18 04:13:06Z

0

You can do it in O(n) using this:

subcomponent_hash = Hash.new { |h, k| h[k] = [] }
subcomponents.each do |sc|
  order = sc[:order][/\d+/]
  subcomponent_hash[order] << sc
end

components.each do |c|
  c[:subcomponents] = subcomponent_hash[c[:order]]
end

edited Aug 18, 2017 at 4:13

answered Aug 17, 2017 at 23:01

Vijay Agrawal

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