How can I change data collection from hash to array?

Question

Now I'm fetching data from another url... Here is my code:

require 'rubygems'
    require 'nokogiri'

    html = page.body

    doc = Nokogiri::HTML(html)
    doc.encoding = 'utf-8'

    rows = doc.search('//table[@id = "MainContent_GridView1"]//tr')
      @details = rows.collect do |row|
          detail = {}
          [
            [:car, 'td[1]/text()'],
            [:article, 'td[2]/text()'],
            [:group, 'td[3]/text()'],
            [:price, 'td[4]/text()'],
          ].each do |name, xpath|
            detail[name] = row.at_xpath(xpath).to_s.strip
          end
          detail
      end
    @details

I tried to do it via array, not a hash. But I get a lot of errors... Are there any ideas? I need it for another method...

also i set data (this result hash) to another car here:

oem_art = []
    @constr_num.each do |o|
      as_oem = get_from_as_oem(o.ARL_SEARCH_NUMBER)
      if as_oem.present?
        oem_art << as_oem
      end
    end    

    @oem_art = oem_art.to_a.uniq

What did you try and what were the errors? Show us the code you are having trouble with, not the code that works. — Alex Wayne, Oct 22 '12 at 17:30
@AlexWayne if you know how to solve, then write it... simple change detail {} to [] and do like detail.car = "td[1]/text()"... That's all i try — byCoder, Oct 22 '12 at 17:46
i need it to operate in view like standart: @lala.each do |lala| lala.name etc... but now i have trouble with more than one record, and need to write lala[:name], when i use hash – PavelBY 28 mins ago — byCoder, Oct 22 '12 at 18:37

score 1 · Accepted Answer · answered Oct 22 '12 at 17:46

1

Do you just want to change a hash into an array? If so, just use the to_a method on your hash.

hash = {:a => "something", :b => "something else"}
array = hash.to_a
array.inspect #=> [[:a, "something"], [:b, "something else"]]

answered Oct 22 '12 at 17:46

i need it to operate in view like standart: @lala.each do |lala| lala.name etc... but now i have trouble with more than one record, and need to write lala[:name], when i use hash – byCoder Oct 22 '12 at 18:07
also if i write = lol[1][:car] i get result, but only for second record – byCoder Oct 22 '12 at 19:52

score 0 · Answer 2 · edited May 23 '17 at 12:27

It looks like you're looking for something like hash['key'] to hash.key in Ruby

The Hash Class doesn't support .key notation by default, OpenStruct creates an Object from the Hash so you can use dot notation to access the properties. Overall it's basically just syntactic sugar with overhead.

Suggested code (from linked answer)

>> require 'ostruct'
=> []
>> foo = {'bar'=>'baz'}
=> {"bar"=>"baz"}
>> foo_obj = OpenStruct.new foo
=> #<OpenStruct bar="baz">
>> foo_obj.bar
=> "baz"

So in your example, you could do:

# Initialised somewhere
require 'ostruct'
DETAIL_INDICES = { 
  :car => 1,
  :article => 2,
  :group => 3,
  :price => 4,
}

# ** SNIP **
@details = rows.map do |row|
  DETAIL_INDICES.inject({}) do |h,(k,v)| 
    h.merge(k => row.at_xpath("td[#{v}]/text()").to_s.strip) 
  end
end.collect { |hash| OpenStruct.new hash }

@details.each do |item|
  puts item.car
end

Of course if performance is a concern you can merge your map&collect (They are the same), but this is just a minor separation for basic semantic differences, although I usually only use map for consistency, so feel free to choose yourself :)

EDIT -- Additional code from your edit simplified

@oem_art = @constr_num.select do |item|
  as_oem = get_from_as_oem(item.ARL_SEARCH_NUMBER)
  as_oem.present?
end

puts @oem_art.uniq

hm, don't understand what you mean((( also if i try to write, without any changes lol[:car] i get something like: can't convert symbol to string — byCoder, Oct 22 '12 at 19:42
Which part would you like me to clarify? What code are you referring to when you say 'without changes', I don't see any code on this page with variables named `lol`? — Rym, Oct 22 '12 at 20:07

How can I change data collection from hash to array?

2 Answers2