in reply to Finding node with attribute XML::LibXML

Volume[@VolumeCategory="L"]

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relative to the root of the document (/) means 
/Volume[@VolumeCategory="L"]

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They fail to find a match since there's no element named Volume at the root of the document. 

/root/Volume[@VolumeCategory="L"]

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would find the node in question, and so would its relative equivalent 

root/Volume[@VolumeCategory="L"]

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It's just like directories. 

$ cd /

$ ls -d ikegami
ls: cannot access ikegami: No such file or directory

$ ls -d /ikegami
ls: cannot access /ikegami: No such file or directory

$ ls -d /home/ikegami
/home/ikegami

$ ls -d home/ikegami
home/ikegami

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Re^2: Finding node with attribute XML::LibXML
by jjap (Monk) on Sep 30, 2014 at 18:06 UTC
    Thanks for the reply.

    I did muff my example as I had been using getElementsByTagName which spared me the need to qualify the full path if may say.

    Should I understand that that methods does not support attribute?
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[d/l]
      If you want to search the whole document, you can use 
      /descendant::Volume[@VolumeCategory="L"]

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      which can be abbreviated to 
      //Volume[@VolumeCategory="L"]

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      Should I understand that that methods does not support attribute?

      If you're asking if getElementsByTagName can filter the returned nodes to retain only those with a specific attribute value, then the answer is no. The only argument it takes is a tag name. You could do 

      my @matching =
   grep {
      my $vc = $_->getAttribute('VolumeCategory');
      defined($vc) && $vc eq "L"
   }
      $doc->getElementsByTagName('Volume');

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      but aforementioned 

      my @matching = $doc->findnodes('//Volume[@VolumeCategory="L"]');

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      is much simpler.

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[d/l]
[select]

        I think you meant to type…

        /descendant::Volume[@VolumeCategory="L"]

        With just one colon, you get…

        XPath error : Undefined namespace prefix
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[d/l]
[select]

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