Need clarification with 'each-do' block in my ruby code - ruby

Question

Given an html file:
<div>
<div class="NormalMid">
<span class="style-span">
"Data 1:"
1
2
</span>
</div>
...more divs
<div class="NormalMid">
<span class="style-span">
"Data 20:"
20
21
22
23
</span>
</div>
...more divs
</div
Using these SO posts as reference:
How do I integrate these two conditions block codes to mine in Ruby?
and
How to understand this Arrays and loops in Ruby?
My code:
require 'nokogiri'
require 'pp'
require 'open-uri'
data_file = 'site.htm'
file = File.open(data_file, 'r')
html = open(file)
page = Nokogiri::HTML(html)
page.encoding = 'utf-8'
rows = page.xpath('//div[#class="NormalMid"]')
details = rows.collect do |row|
detail = {}
[
[row.children.first.element_children,row.children.first.element_children],
].each do |part, link|
data = row.children[0].children[0].to_s.strip
links = link.collect {|item| item.at_xpath('#href').to_s.strip}
detail[data.to_sym] = links
end
detail
end
details.reject! {|d| d.empty?}
pp details
The output:
[{:"Data 1:"=>
["http://www.site.com/data/1",
"http://www.site.com/data/2"]},
...
{:"Data 20 :"=>
["http://www.site.com/data/20",
"http://www.site.com/data/21",
"http://www.site.com/data/22",
"http://www.site.com/data/20",]},
...
}]
Everything is going good, exactly what I wanted.
BUT if you change these lines of code:
detail = {}
[
[row.children.first.element_children,row.children.first.element_children],
].each do |part, link|
to:
detail = {}
[
[row.children.first.element_children],
].each do |link|
I get the output of
[{:"Data 1:"=>
["http://www.site.com/data/1"]},
...
{:"Data 20 :"=>
["http://www.site.com/data/20"]},
...
}]
Only the first anchor href is stored in the array.
I just need some clarification on why its behaving that way because the argument part in the argument list is not being used, I figure I didn't need it there. But my program doesn't work correctly if I delete the corresponding row.children.first.element_children as well.
What is going on in the [[obj,obj],].each do block? I just started ruby a week ago, and I'm still getting used to the syntax, any help will be appreciated. Thank You :D
EDIT
rows[0].children.first.element_children[0] will have the output
Nokogiri::XML::Element:0xcea69c name="a" attributes=[#<Nokogiri::XML::Attr:0xcea648
name="href" value="http://www.site.com/data/1">] children[<Nokogiri::XML::Text:0xcea1a4
"1">]>
puts rows[0].children.first.element_children[0]
1

Answer 1

You made your code overly complicated. Looking at your code,it seems you are trying to get something like below:
require 'nokogiri'
doc = Nokogiri::HTML::Document.parse <<-eotl
<div>
<div class="NormalMid">
<span class="style-span">
"Data 1:"
1
2
</span>
</div>
<div class="NormalMid">
<span class="style-span">
"Data 20:"
20
21
22
23
</span>
</div>
</div
eotl
rows = doc.xpath("//div[#class='NormalMid']/span[#class='style-span']")
val = rows.map do |row|
[row.at_xpath("./text()").to_s.tr('"','').strip,row.xpath(".//#href").map(&:to_s)]
end
Hash[val]
# => {"Data 1:"=>["http://site.com/data/1", "http://site.com/data/2"],
# "Data 20:"=>
# ["http://site.com/data/20",
# "http://site.com/data/21",
# "http://site.com/data/22",
# "http://site.com/data/23"]}
What is going on in the [[obj,obj],].each do block?
Look the below 2 parts:
[[1],[4,5]].each do |a|
p a
end
# >> [1]
# >> [4, 5]
[[1,2],[4,5]].each do |a,b|
p a, b
end
# >> 1
# >> 2
# >> 4
# >> 5