Perl-XML:LibXML——获取具有某些属性的元素-Perl-XML::LibXML-gettingelementsthathavecertainattributes

I have a problem I am hoping someone can help with...

我有个问题，我希望有人能帮忙……

I have the following example xml structure:

我有以下示例xml结构:

    
       
       Damian Conway
       0596001738
       542
       
    
    
       
       Tom Christiansen
       Nathan Torkington
       0596003137
       964
       
    
    
       
       Mark Phillips
       John Chappell
       076455106X
       392
       
    

Code that I thought should work:

我认为应该工作的代码:

use warnings;
use strict;

use XML::LibXML;

my $parser = XML::LibXML->new();
my $xmldoc = $parser->parse_file('/path/to/xmlfile.xml');

my $width = "145";

my $query = "//book/image[\@width/text() = '$width']/author/text()";

foreach my $data ($xmldoc->findnodes($query)) {
    print "Results: $data\n";
}

Expected output:

预期的输出:

Damian Conway Tom Christiansen

Damian Conway Tom Christiansen

but I do not get anything returned.

但我没有得到任何回报。

I thought this would match the text content of any "author" elements within a "book" element which also contains an "image" element with an attribute 'width' that has a value of 145.

我认为这将匹配“book”元素中的任何“author”元素的文本内容，该元素还包含一个“image”元素，其属性“width”的值为145。

I'm sure I'm overlooking something very obvious here but cannot work out what I am doing wrong.

我肯定我忽略了一些很明显的东西，但却不能算出我做错了什么。

Your help is much appreciated thanks

非常感谢您的帮助

3 个解决方案

#!/usr/bin/perl
use warnings;
use strict;

use XML::LibXML;

my $parser = XML::LibXML->new();
my $xmldoc = $parser->parse_file('1.xml');

my $width = "145";

my $query = "//book[image/\@width = '$width']/author/text()";

foreach my $data ($xmldoc->findnodes($query)) {
    print "Results: ", $data->toString, "\n";
}

for my $book ($xmldoc->findnodes('/library/book')) {
    my $image_width = $book->findvalue('image/@width');
    next if !$image_width || $image_width ne '145';

    for my $data ($book->findnodes('author/text()')) {
        print "Results: ", $data->toString, "\n";
    }
}