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in reply to XPath with node names and attributes...

Perhaps It would help if you provide some example code and xml that demonstrates the problem you are having.
  • Comment on Re: XPath with node names and attributes...

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Re^2: XPath with node names and attributes...
by biswanath_c (Beadle) on Oct 16, 2009 at 17:33 UTC

    okay! here we go. I am just giving an example here that I tested and which demonstrates my problem:


    The XML: 
    <root>
    <head>
        <node1 attr1="Node1 Attribute">
                Node1 Value
        </node1>
    </head>
</root>

    [download]


    The PERL script that tries to read the attribute: 

    use XML::LibXML;


    $inp             = $ARGV[0];

    # create object
    my $parser = XML::LibXML->new();


    # read input XML file
    my $inp_tree = $parser->parse_file($inp);
    my $inp_root = $inp_tree->getDocumentElement;
    
    my $root_text = $inp_root->toString();
    
    $rule_source = "head/node1@attr1";
    
    my @inp_search_nodes = $inp_root->findnodes($rule_source);
                    
    my $inp_search_results = scalar @inp_search_nodes;
                                                                    
    if ( 0 == $inp_search_results )
    {
        print "XPath $rule_source not found! \n";
                    
    }
    else
    {
        my $path_text = $inp_search_nodes[ 0 ]->findvalue(".");
            print "Xpath ->:  $path_text\n";

        my $val = $inp_search_nodes[ 0 ]->textContent();              
+                            
            print "Value of XPath $rule_source : $val \n";
    }

    [download]

    If i search for XPath head/node1@attr1 , the code works fine and fetches the value of the node.

    If i use XPath XPath /head/node1@attr1 , the program gives the error :
     "/head/node1 not found!"

    If i use the Xpath, i get this error:
     Invalid expression

    If I use the XPath "/head/node1/@attr1", I get this error:
     Invalid expression


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      Didn't have a chance to test your example, but I think this is the problem:

      $rule_source = "head/node1@attr1";

      [download]

      Perl thinks you want to insert the contents of an array called @attr1 into the string because you used double quotes. Since there is no such array your $rule_source ends up with just "head/node1". Either escape the '@' or use a single quoted string as in the examples below:

      $rule_source = "head/node1\@attr1";
# or
$rule_source = 'head/node1@attr1';

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