xpath query

mojo-jojo has asked for the wisdom of the Perl Monks concerning the following question:

I am trying to find tags in an xml file which do not have a particular child. I am using the following code but it gives me an error Use of uninitialized value $local in substitution (s///) at /usr/local/lib/perl5/site_perl/5.10.0/XML/XPath/Node/Element.pm line 138.



my $xp = XML::XPath->new( filename => $_[0] );

    my $nodeset = $xp->find('//descendant-or-self::node()[local-name(.
+) = dependency and not(child::version)] ');    # find all authors

    foreach my $node ( $nodeset->get_nodelist ) {
        print XML::XPath::XMLParser::as_string($node)."\n\n";
    }
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A snippet of xml file is given below


<project>
  <dependency>
            <!-- find all such dependency tags -->
            <groupId>com.solarmetric</groupId>
            <artifactId>kodo-jdo-runtime</artifactId>
  </dependency>
  <dependency>
            <groupId>javax.jdo</groupId>
            <artifactId>jdo</artifactId>
            <version>1.0.2</version>
  </dependency>

</project>
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Replies are listed 'Best First'.
Re: xpath query by Anonymous Monk on Dec 27, 2011 at 11:02 UTC
You're doing it wrong. `use XML::LibXML qw(); XML::LibXML ->load_xml(string => <<'XML')->find('//dependency[not(version)]'); <project> <dependency> <!-- find all such dependency tags --> <groupId>com.solarmetric</groupId> <artifactId>kodo-jdo-runtime</artifactId> </dependency> <dependency> <groupId>javax.jdo</groupId> <artifactId>jdo</artifactId> <version>1.0.2</version> </dependency> </project> XML` [download] The expression returns a XML::LibXML::NodeList referencing a single XML::LibXML::Element representing the first `dependency` element.find(	[reply] [d/l]
Re^2: xpath query by ikegami (Patriarch) on Dec 27, 2011 at 11:13 UTC
His XPath searched for "dependency" elements regardless of their namespace. Your XPath searches for "dependency" elements in the null namespace.	[reply]
Re^2: xpath query by mojo-jojo (Novice) on Dec 28, 2011 at 06:03 UTC
why cant I find with the xpath query I have and the code I am using, cant I change the query to make it work?	[reply]
Re^3: xpath query by mojo-jojo (Novice) on Dec 28, 2011 at 10:27 UTC
Found the solution by using the following code `my $xp = XML::XPath->new( filename => $_[0] ); my $nodeset = $xp->find('//dependency[not(child::version)] '); +# find all authors foreach my $node ( $nodeset->get_nodelist ) { print XML::XPath::XMLParser::as_string($node)."\n\n"; }` [download]	[reply] [d/l]
Re: xpath query by choroba (Cardinal) on Dec 28, 2011 at 14:28 UTC
Strings must be quoted in XPath, i.e. `local-name(.)="dependency"` [download]	[reply] [d/l]