REXML parsing an XML in ruby

Question

Folks,

I am using REXML for a sample XML file:

<Accounts title="This is the test title">  
    <Account name="frenchcustomer">  
            <username name = "frencu"/>  
            <password pw = "hello34"/>  
            <accountdn dn = "https://frenchcu.com/"/>  
            <exporttest name="basic">  
                    <exportname name = "basicexport"/>  
                    <exportterm term = "oldschool"/>  
            </exporttest>  
    </Account>  
    <Account name="britishcustomer">  
            <username name = "britishcu"/>  
            <password pw = "mellow34"/>  
            <accountdn dn = "https://britishcu.com/"/>  
            <exporttest name="existingsearch">  
                    <exportname name = "largexpo"/>  
                    <exportterm term = "greatschool"/>  
            </exporttest>  
    </Account>  
</Accounts>

I am reading the XML like this:

@data = (REXML::Document.new file).root
@dataarr = @@testdata.elements.to_a("//Account")

Now I want to get the username of the frenchcustomer, so I tried this:

@dataarr[@name=fenchcustomer].elements["username"].attributes["name"]

this fails, I do not want to use the array index, for example

@dataarr[1].elements["username"].attributes["name"]

will work, but I don't want to do that, is there something that i m missing here. I want to use the array and get the username of the french user using the Account name.

Thanks a lot.

I've updated my answer, so there is an example for getting element with name 'frenchcustomer' without specifying an index — louiscoquio, Feb 13 '12 at 22:22

louiscoquio · Answer 1 · 2012-02-13T22:18:30.467

I recommend you to use XPath.

For the first match, you can use first method, for an array, just use match.

The code above returns the username for the Account "frenchcustomer" :

REXML::XPath.first(yourREXMLDocument, "//Account[@name='frenchcustomer']/username/@name").value

If you really want to use the array created with @@testdata.elements.to_a("//Account"), you could use find method :

french_cust_elt = the_array.find { |elt| elt.attributes['name'].eql?('frenchcustomer') }
french_username = french_cust_elt.elements["username"].attributes["name"]

Dave Newton · Answer 2 · 2012-02-13T21:37:34.093

1

puts @data.elements["//Account[@name='frenchcustomer']"]
      .elements["username"]
      .attributes["name"]

If you want to iterate over multiple identical names:

@data.elements.each("//Account[@name='frenchcustomer']") do |fc|
  puts fc.elements["username"].attributes["name"]
end

edited Feb 13 '12 at 21:37

answered Feb 13 '12 at 21:31

Dave Newton

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knut · Answer 3 · 2012-02-13T21:33:51.910

I don't know what your @@testdata are, I tried with the following testcode:

require "rexml/document"

@data = (REXML::Document.new DATA).root 
@dataarr = @data.elements.to_a("//Account")

# Works
p @dataarr[1].elements["username"].attributes["name"]

#Works not
#~ p @dataarr[@name='fenchcustomer'].elements["username"].attributes["name"]

#@dataarr is an array
@dataarr.each{|acc|
  next unless acc.attributes['name'] =='frenchcustomer'
  p acc.elements["username"].attributes["name"]
}

#@dataarr is an array
puts "===Array#each"
@dataarr.each{|acc|
  next unless acc.attributes['name'] =='frenchcustomer'
  p acc.elements["username"].attributes["name"]
}

puts "===XPATH"
@data.elements.to_a("//Account[@name='frenchcustomer']").each{|acc|
  p acc.elements["username"].attributes["name"]
}

__END__
<Accounts title="This is the test title">
 <Account name="frenchcustomer">
 <username name = "frencu"/>
 <password pw = "hello34"/>
 <accountdn dn = "https://frenchcu.com/"/>
 <exporttest name="basic">
 <exportname name = "basicexport"/>
 <exportterm term = "oldschool"/>
 </exporttest>
 </Account>
 <Account name="britishcustomer">
 <username name = "britishcu"/>
 <password pw = "mellow34"/>
 <accountdn dn = "https://britishcu.com/"/>
 <exporttest name="existingsearch">
 <exportname name = "largexpo"/>
 <exportterm term = "greatschool"/>
 </exporttest>
 </Account>
 </Accounts>

I'm not very familiar with rexml, so I expect there is a better solution. But perhaps aomebody can take my code to build a better solution.

REXML parsing an XML in ruby

3 Answers3