Ruby 2.2 Using REXML
Question
I have followed much tutorials about Ruby 2.2 and REXML. This is an example of my xml:
<msg user='Karim'><body action='ChkUsername' r='0'><ver v='153' /></body></msg>
And this is what I currently have as code:
xml = "<msg user='Karim'><body action='ChkUsername' r='0'><ver v='153' /></body></msg>"
doc = Document.new xml
puts doc.root.attributes[action]
That won't work. An error pops out. undefined local variable or method 'action' for #{classname} (NameError)
1 answers
solution1
2 ACCPTED 2015-04-14 16:03:56
You can't randomly assume variables exist. The token action will be interpreted as a reference (eg, a variable or method call) since it's not a string or symbol. You don't have that variable or method, so you get an error telling you precisely what's wrong.
puts doc.root.attributes['action']
The root of your document is the <msg> tag. The <msg> tag does not have an attribute action . It has a user attribute, accessible as you'd expect:
> require 'rexml/document'
> xml = "<msg user='Karim'><body action='ChkUsername' r='0'><ver v='153' /></body></msg>"
> doc = REXML::Document.new(xml)
> doc.root.attributes['user']
=> "Karim"
The action attribute is nested further in the document, in the <body> element.
There are a number of ways to interrogate a document (all covered in the tutorial, btw), eg,
> doc.elements.each('//body') do |body|
> puts body.attributes['action']
> end
ChkUsername
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.