如何从 Perl 中的 XML 文档中删除重复注释？

Question

我有一个带有重复节点的站点地图视频文件 xml :

<?xml version="1.0"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:video="http://www.google.com/schemas/sitemap-video/1.1"> 
<url>
<loc>http://www.tubtun.com/video/Samsung_42Channel_Wireless_SoundStand</loc>
<video:video>
    <video:title>Samsung 42Channel Wireless SoundStand</video:title>
    <video:description>Samsung 4.2Channel Wireless SoundStand</video:description>
    <video:thumbnail_loc>http://www.tubtun.com/media/files_thumbnail/user91/pl_5364844b0dc.jpg</video:thumbnail_loc>
    <video:player_loc>http://www.tubtun.com/modules/vPlayer/vPlayer.swf?f=http://www.tubtun.com/modules/vPlayer/vPlayercfg.php?fid=844b0dc2c7258f4de11</video:player_loc>
    <video:publication_date>2015-01-27</video:publication_date>
</video:video>
</url>
<url>
<loc>http://www.tubtun.com/video/Samsung_42Channel_Wireless_SoundStand</loc>
<video:video>
    <video:title>Samsung 42Channel Wireless SoundStand</video:title>
    <video:description>Samsung 4.2Channel Wireless SoundStand</video:description>
    <video:thumbnail_loc>http://www.tubtun.com/media/files_thumbnail/user91/pl_5364844b0dc.jpg</video:thumbnail_loc>
    <video:player_loc>http://www.tubtun.com/modules/vPlayer/vPlayer.swf?f=http://www.tubtun.com/modules/vPlayer/vPlayercfg.php?fid=844b0dc2c7258f4de11</video:player_loc>
    <video:publication_date>2015-01-27</video:publication_date>
</video:video>
</url>
.....

我已经编写了一个 perl 脚本来删除这些重复数据：

use strict;
use warnings;
use XML::LibXML;

my $file = 'sitemap.xml';
my $doc = XML::LibXML->load_xml( location => $file );

my %seen;
foreach my $uni ( $doc->findnodes('//url') ) {  # 'university' nodes only

    my $name = $uni->find('video:title');

    print "'$name' duplicated\n",
      $uni->unbindNode() if $seen{$name}++;  # Remove if seen before
}

$doc->toFile('clarified.xml'); # Print to file

很遗憾，文件 "clarified.xml" 与 sitemap.xml 相同。

我不知道我的脚本有什么问题。

Answer 1

我不太清楚为什么你的 XML::LibXML 不工作，尽管如评论中所述 - 如果它不与 find 一起工作，那将是它的根源。

我将提供一个使用 XML::Twig 确实有效的替代方案。

#!/usr/bin/env perl 
use strict;
use warnings;
use XML::Twig; 

my $file = 'test3.xml';

my %seen;

sub delete_url_if_seen {
   my ( $twig, $url ) = @_; 
   my $name = $url -> get_xpath('./video:video/video:title',0) -> trimmed_text;
   if ( $seen{$name}++ ) { $url -> delete; };
}

my $twig = XML::Twig -> new ( 'pretty_print' => 'indented_a', 
                   'twig_handlers' => { 'url' => \&delete_url_if_seen } );
$twig -> parsefile_inplace ( $file );

Answer 2

我成功了，这是代码，我尝试了

中提供的解决方案

use strict;
use warnings;
use XML::LibXML;

my $file = 'sitemap.xml';
my $doc = XML::LibXML->load_xml( location => $file );

my %seen;
foreach my $uni ( $doc->findnodes("//*[name() ='url']") ) {  # 'university' nodes only

    my $name = $uni->find('//video:title');
    print "'$name' duplicated\n",
      $uni->unbindNode() if $seen{$name}++;  # Remove if seen before
}

$doc->toFile('clarified.xml'); # Print to file

Answer 3

您应该使用 XPathContext 并注册视频和默认命名空间。您还应该调用 findvalue 以获取字符串形式的标题。

my $xpc = XML::LibXML::XPathContext->new();
$xpc->registerNs(sitemap => 'http://www.sitemaps.org/schemas/sitemap/0.9');
$xpc->registerNs(video   => 'http://www.google.com/schemas/sitemap-video/1.1');
for my $node ($xpc->findnodes('//sitemap:url', $doc)) {
    my $name = $xpc->findvalue('video:title', $node);
    ...
}

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