A simple example - XML from a Ruby program

Archive - Originally posted on "The Horse's Mouth" - 2010-04-10 07:16:50 - Graham Ellis
The REXML module is supplied with the Ruby distribution and provides a neat way of handling XML data in Ruby. There is a very wide range of methods available, though, and sometimes it's hard to see the wood for the trees.

So here - to start - is the [full source] of an application which reads an RSS feed and splits out the title elements. I've actually done the job twice - once by finding the elements directly, and then (slighty more sophisticated) by accessing elements within elements.

require 'rexml/document'

include REXML

 

file = File.new("myrssfeed.xml")

doc = Document.new(file)

 

# -------------  Reading from the document structure

# -------------  This is an RSS feed - few attributes ;-)

  

doc.elements.each("rss/channel/item/title") do |element| 

  puts element

end

  

puts " AGAIN -----------------"

  

doc.elements.each("rss/channel/item") do |element| 

  element.elements.each("title") do |ttl|

    puts ttl

  end

end

Sample output using [this data]:

Dorothy-2:ra10 grahamellis$ ruby x1.rb 

<title>History is all around us</title>

<title>A more informed decision than ever before</title>

<title>For loop - checked once, or evety time?  Ruby v Perl comparison and contrast</title>

<title>__index and __newindex in Lua - metatable methods</title>

<title>Old trackways and routes near Melksham</title>

<title>The bull on the footpath</title>

<title>A walk on the Kennet and Avon</title>

<title>Error trapping in Lua - no exceptions.</title>

<title>Hotel booking in Melksham made easy!</title>

<title>A walk within without - Melksham Without</title>

<title>Lua Metatables</title>

<title>First and last match with Regular Expressions</title>

<title>Is Lua an Object Oriented language?</title>

<title>The same very simple program in many different programming languages</title>

<title>Lua tables - they are everything</title>

 AGAIN -----------------

<title>History is all around us</title>

<title>A more informed decision than ever before</title>

<title>For loop - checked once, or evety time?  Ruby v Perl comparison and contrast</title>

<title>__index and __newindex in Lua - metatable methods</title>

<title>Old trackways and routes near Melksham</title>

<title>The bull on the footpath</title>

<title>A walk on the Kennet and Avon</title>

<title>Error trapping in Lua - no exceptions.</title>

<title>Hotel booking in Melksham made easy!</title>

<title>A walk within without - Melksham Without</title>

<title>Lua Metatables</title>

<title>First and last match with Regular Expressions</title>

<title>Is Lua an Object Oriented language?</title>

<title>The same very simple program in many different programming languages</title>

<title>Lua tables - they are everything</title>

Dorothy-2:ra10 grahamellis$

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A simple example - XML from a Ruby program