Nokogiri is a Ruby library for parsing HTML and XML documents. To search for elements with a specific CSS class using Nokogiri, you can use the .css method, which allows you to select elements using CSS selectors.
Here is a step-by-step guide on how to search for elements with a specific CSS class using Nokogiri:
- Install Nokogiri: If you haven't already, you need to install the Nokogiri gem. You can do this by running the following command in your terminal:
gem install nokogiri
- Require Nokogiri in Your Ruby Script: At the top of your Ruby script, require the Nokogiri library:
require 'nokogiri'
- Parse the HTML Document: Use Nokogiri to parse the HTML document from which you want to search elements. This can be done by reading the HTML content from a file, a string, or directly from a web request.
# If you have an HTML file
html_content = File.read('example.html')
# If you have an HTML string
html_content = '<div class="my-class">Content</div>'
# Parse the HTML content
doc = Nokogiri::HTML(html_content)
- Search for Elements with a Specific CSS Class: Use the
.cssmethod with the appropriate CSS selector to find all elements that have the specific class.
# Search for elements with the class "my-class"
elements = doc.css('.my-class')
- Iterate Over and Work with the Elements: Once you have selected the elements, you can iterate over them and work with each element as needed.
# Iterate over each element with the class "my-class"
elements.each do |element|
puts element.content # Output the content of each element
end
Here's a full example that combines all the steps:
require 'nokogiri'
# Sample HTML content
html_content = <<-HTML
<html>
<head>
<title>My webpage</title>
</head>
<body>
<div class="my-class">Content 1</div>
<div class="my-class">Content 2</div>
<div class="other-class">Other Content</div>
</body>
</html>
HTML
# Parse the HTML content
doc = Nokogiri::HTML(html_content)
# Search for elements with the class "my-class"
elements = doc.css('.my-class')
# Iterate over each element with the class "my-class"
elements.each do |element|
puts element.content # Output the content of each element
end
When you run the above Ruby script, it will output the content of each div element with the class my-class:
Content 1
Content 2
Remember that the .css method can take any valid CSS selector, so you can also search for elements by tag name, ID, attribute, or any combination thereof.
