extract links (URLs), with nokogiri in ruby, from a href html tags?

问题

I want to extract from a webpage all URLs how can I do that with nokogiri?

example:

<div class="heat">
   <a href='http://example.org/site/1/'>site 1</a>
   <a href='http://example.org/site/2/'>site 2</a>
   <a href='http://example.org/site/3/'>site 3</a>
</diV>

result should be an list:

l = ['http://example.org/site/1/', 'http://example.org/site/2/', 'http://example.org/site/3/'

回答1:

You can do it like this:

doc = Nokogiri::HTML.parse(<<-HTML_END)
<div class="heat">
   <a href='http://example.org/site/1/'>site 1</a>
   <a href='http://example.org/site/2/'>site 2</a>
   <a href='http://example.org/site/3/'>site 3</a>
</div>
<div class="wave">
   <a href='http://example.org/site/4/'>site 4</a>
   <a href='http://example.org/site/5/'>site 5</a>
   <a href='http://example.org/site/6/'>site 6</a>
</div>
HTML_END

l = doc.css('div.heat a').map { |link| link['href'] }

This solution finds all anchor elements using a css selector and collects their href attributes.

回答2:

ok this code works perfect for me, thanks to sris

p doc.xpath('//div[@class="heat"]/a').map { |link| link['href'] }

来源：https://stackoverflow.com/questions/856706/extract-links-urls-with-nokogiri-in-ruby-from-a-href-html-tags