How to display the values of a hashes nested within an array

Question

When I send a request to a function I get back an array with a nested hashes looking like this (i formatted it a bit for readability):

@variable = [{:"Some ID"=>1, :"Some area"=>"Berlin", :"Company Name"=>"the dummy company", :"A Date"=>2014-01-17 02:15:53 +0100, :"First Name"=>"Michael", :"Last Name"=>"Myers", :"Number Average"=>#<BigDecimal:7fcf546f3da0,'0.5E1',9(18)>, :"Number One"=>5, :"Number Two"=>5, :Comment=>"Tippi Toppi", :Count=>2},
{:"Some ID"=>2, :"Some area"=>"Berlin", :"Company Name"=>"the dummy company", :"A Date"=>2014-01-17 02:15:54 +0100, :"First Name"=>"Michael", :"Last Name"=>"Myers", :"Number Average"=>#<BigDecimal:7fcf546f3bc0,'0.5E1',9(18)>, :"Number One"=>5, :"Number Two"=>5, :Comment=>"OHA", :Count=>2}]

What would I like to do? I want to display the values of the hashes in a table like:

ID | Some Area | Company Name | ...

1 | Berlin | The Dummy company | ...

2 | Berlin | The Dummy company | ...

I have found this answer and tried it, but I get a undefined method 'data' for #<Hash: ... >.

View

- headers = @variable.map(&:data).flat_map(&:keys).uniq #<< error points here

      %tr
        - headers.each do |key|
          %th= key

      - @variable.each do |tr|
        %tr
          - header.each do |key|
            %td= tr.data[key]

Wizard of Ogz · Accepted Answer · 2014-02-09 06:09:18Z

1

From the thread you referenced data is an attribute and is not a method on the standard Ruby Hash. Other than that your code seemed fine.

- headers = @variable.flat_map(&:keys).uniq #<< error used to occur here

  %tr
    - headers.each do |key|
      %th= key

  - @variable.each do |tr|
    %tr
      - headers.each do |key|
        %td= tr[key]

Aside: It is good practice to keep logic out of the views, so I'd recommend moving this code into a controller or model headers = @variable.flat_map(&:keys).uniq

answered Feb 9, 2014 at 6:09

Wizard of Ogz

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1 Comment

tomr Over a year ago

This works like a charm! Thanks! As for moving the logic - will do so - thanks for the reminder :)

thorsten müller · Accepted Answer · 2014-02-08 15:10:46Z

0

If I see this right your main question would be how to collect the hash keys into a header array. (I'm assuming all hashes in @variable have an identical structure)

@headers = @variables.first.keys

should be all you need here.

@rows = @variables.map(&:values)

should give you the rows with data only.

answered Feb 8, 2014 at 15:10

thorsten müller

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2 Comments

tomr Over a year ago

Hey Thorsten - it now says "undefined method keys for nil:NilClass". If I leave the "first" and just add "keys" it says "undefined method keys for array[]". Any idea?

Wizard of Ogz Over a year ago

@timo Your array was most likely empty. Or the first element of the array was nil.

Peeyush · Accepted Answer · 2014-02-08 15:22:59Z

0

A simple way would be

<% @variable.each do |variable| %>
  <%= variable["some id"] | variable["some area"]... %>
<% end %>

Edit: To make it dynamic, you can try something like

<% @variable.each do |variable| %>
  <% variable.each do |key,value| %>
    <%= key : value %>
  <% end %>
<% end %>

edited Feb 8, 2014 at 15:22

answered Feb 8, 2014 at 14:49

Peeyush

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1 Comment

tomr Over a year ago

But then it is not dynamic anymore. I would like it to be dynamic so that it changes in case I want to change the array/hash

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