Perl删除重复的XML标签 [英] Perl remove duplicate XML tags

问题描述

我有以下XML文件:

<d:entry id="a" d:title="a">
  <d:index d:value="a" d:title="a"/>
  <d:index d:value="b" d:title="b"/>
  <d:index d:value="a" d:title="a"/>
  <d:index d:value="c" d:title="c"/>
  <d:index d:value="b" d:title="b"/>
  <d:index d:value="a" d:title="a"/>
  <d:index d:value="b" d:title="b"/>
  <div>This is the content for entry.</div>
</d:entry>
<d:entry id="b" d:title="b">
  <d:index d:value="a" d:title="a"/>
  <d:index d:value="b" d:title="b"/>
  <div>This is the content for entry.</div>
</d:entry>

(添加了空格以提高可读性.)

(Whitespace added for readability.)

有一些<d:index的重复项，我需要除去所有重复项，并且只保留一个唯一的<d:index.所需的效果是这样的:

There are some duplicates of <d:index, I need to get rid of all the duplicates and only keep one unique <d:index. The desired effect is like this:

<d:entry id="a" d:title="a">
   <d:index d:value="a" d:title="a"/>
   <d:index d:value="b" d:title="b"/>
   <d:index d:value="c" d:title="c"/>
   <div>This is the content for entry.</div>
</d:entry>
<d:entry id="b" d:title="b">
  <d:index d:value="a" d:title="a"/>
  <d:index d:value="b" d:title="b"/>
  <div>This is the content for entry.</div>
</d:entry>

我可以为此目的在某些编辑器中进行正则表达式替换，但需要多次执行，我想知道Perl是否有某种方法可以一次运行.

I can do the regex replacement in some editors for that purpose, but it needs to be done multiple times, I was wondering if Perl has some ways to do this in one run.

推荐答案

以下是过滤重复项的常用方法:

The following is a common way to filter out duplicates:

my @filtered = grep { !$seen{$_}++ } @unfiltered;

这可以根据您的需要进行调整，如以下代码片段所示:

This can be adapted to your needs, as shown in the following snippet:

my %seen;
for my $index_node ($xpc->findnodes('d:index', $entry_node)) {
   my $value = $xpc->findvalue('@d:value', $index_node);
   my $title = $xpc->findvalue('@d:title', $index_node);
   if ($seen{$value}{$title}++) {
      $index_node->unbind();
   }
}

(我使用了我首选的解析器XML :: LibXML，因为您没有提到您使用的是哪个解析器.)

(I used my preferred parser, XML::LibXML, since you didn't mention which parser you were using.)

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