Need a help to get a good start with Nokogiri #css syntax

Rails
1

Hi,

I am learning “Nokogiri”. But I am quite good Nokogiri’s #xpath
technique.But wanted to learn also #css. So started to search online
materials to see how other writes a code using CSS techniques. Doing so
I got one interesting code as below:

========================================================
#Google laptop search

require “nokogiri”
require “open-uri”
result = open(“laptop - Google Search”, “User-Agent” =>
“HTTP_USER_AGENT:Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US)
AppleWebKit/534.13 (KHTML, like Gecko) Chrome/9.0.597.47
Safari/534.13”).read()

#puts result.inspect
doc = Nokogiri::HTML(result)

puts “result list”
#puts doc
puts doc.css(“#resultStats”).text

puts “related searches”
doc.css(“#trev a”).each do |x|
puts “#{x.text} => #{x[:href]}”
end

puts “results”

doc.css(“#ires ol li”).each do |x|
node = x.at_css(“div a”)
puts node[:href]
puts node.text
desc_node = x.at_css(“div div.s”)
puts node.text
end

But I am not comfortable with some notation used here,so thought if
anyone out there help me to redirect to a resource where I can learn
such techniques.

My hard confusion is with the below lines:

***** “#ires ol li” *****

  • when to write this way?
  • what # stands for? Looking at the source page I saw ires is one
    id. – when I need to use such # and when .?
  • Is there any other operators like # and . when using css?
2

On Wednesday, May 1, 2013 1:43:06 PM UTC+1, Ruby-Forum.com User wrote:

But I am not comfortable with some notation used here,so thought if
anyone out there help me to redirect to a resource where I can learn
such techniques.

You need to read up on css selectors

My hard confusion is with the below lines:

***** “#ires ol li” *****

  • when to write this way?
  • what # stands for? Looking at the source page I saw ires is one
    id. – when I need to use such # and when .?

#foo finds an element with id foo whereas .foo finds an element with
class
foo. Which one to use depends on the markup.

  • Is there any other operators like # and . when using css?

Yes, there are a whole bunch, such as the pseudo selectors (:not,
:nth-child), attribute selectors etc.

has fairly exhaustive info

Fred

3

Frederick C. wrote in post #1107477:

On Wednesday, May 1, 2013 1:43:06 PM UTC+1, Ruby-Forum.com User wrote:

Yes, there are a whole bunch, such as the pseudo selectors (:not,
:nth-child), attribute selectors etc.

CSS selectors - Learn web development | MDN

has fairly exhaustive info

@Fred Thank you very much! The source link you shared is exactly what I
was looking for. For Nokogiri - I think only the selectors part would be
great to read to get start Nokogiri right?

4

I am searching for a good example for the below method:

Nokogiri::XML::Node#matches?
(File: README — Documentation for nokogiri (1.15.2))
Nokogiri::XML::Node#fragment
(File: README — Documentation for nokogiri (1.15.2))

Any one out there,ever used these 2 methods. I need an example against
each,so your help will be much appreciated.

Thanks

5

check out this reference:

http://www.w3schools.com/cssref/css_selectors.asp

6

[email protected] wrote in post #1110301:

check out this reference:

http://www.w3schools.com/cssref/css_selectors.asp

No Sir! I asked for the examples of the 2 methods,if any one ever used:

Nokogiri::XML::Node#matches?
Nokogiri::XML::Node#fragment

7

[email protected] wrote in post #1110301:

check out this reference:

http://www.w3schools.com/cssref/css_selectors.asp

here is another link: