CODEWITHSUNDEEP
rubyregex
Bala
Bala

Reputation: 11244

how to get html class values using regular expression in ruby

I have this below string from which I want to extract class values "ruby", "html", "java". My objective here is understanding / learning regular expressions that I have always dreaded :-).

<div class="ruby" name="ruby_doc">
<div class="html" name="html_doc">
<div class="java" name="java_doc">

This is what I have so far 

str = <<END
<div class="ruby" name="ruby_doc">
<div class="html" name="html_doc">
<div class="java" name="java_doc">
END

str.scan(/"[^"]+/) #=> returns
["\"ruby", "\" name=", "\"ruby_doc", "\">\n<div class=", "\"html",...]

str.scan(/class="[^"]+/) #=> ["class=\"ruby", "class=\"html", "class=\"java"]

str.scan(/"(\w)+?"/) #=> [["ruby"], ["ruby_doc"], ["html"], ["html_doc"], ...]

Upvotes: 1

Views: 1472

Answers (5)

pguardiario
pguardiario

Reputation: 54984

Howsabout:

str.scan /"(.*?)"/
#=> [["ruby"], ["ruby_doc"], ["html"], ["html_doc"], ["java"], ["java_doc"]]

Upvotes: -3

sawa
sawa

Reputation: 168091

str.scan(/\b(?<=class=\")[^"]+(?=\")/)
# => ["ruby", "html", "java"]

Upvotes: 7

Marcelo De Polli
Marcelo De Polli

Reputation: 29291

You really should use Nokogiri as per @Arup's answer. But, if you insist...

str.scan(/(?:class\=\")(\w+)(?:\")/).flatten

Live test in Ruby console

2.0.0p247 :001 > str = <<END
2.0.0p247 :002"> <div class="ruby" name="ruby_doc">
2.0.0p247 :003"> <div class="html" name="html_doc">
2.0.0p247 :004"> <div class="java" name="java_doc">
2.0.0p247 :005"> END
 => "<div class=\"ruby\" name=\"ruby_doc\">\n<div class=\"html\" name=\"html_doc\">\n<div class=\"java\" name=\"java_doc\">\n" 
2.0.0p247 :006 > str.scan(/(?:class\=\")(\w+)(?:\")/).flatten
 => ["ruby", "html", "java"]

Upvotes: 1

bsd
bsd

Reputation: 2717

Parsing HTML with regex is not recommended. If you had to write a somewhat ok regex, then you could try with

 str.scan /<div\s+class=\s*"([^"]+)/
 #=> [["ruby"], ["html"], ["java"]]

Upvotes: 2

Arup Rakshit
Arup Rakshit

Reputation: 118271

Use Nokogiri for this :

require 'nokogiri'

doc = Nokogiri::HTML::Document.parse <<-_html_
<div class="ruby" name="ruby_doc">
<div class="html" name="html_doc">
<div class="java" name="java_doc">
_html_

# to get values of class attribute
doc.xpath('//div/@class').map(&:to_s)
# => ["ruby", "html", "java"]
# to get values of name attribute
doc.xpath('//div/@name').map(&:to_s)
# => ["ruby_doc", "html_doc", "java_doc"]

Upvotes: 3

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