xml - 如何从 perl 中的 xml 中获取所需的元素？

Question

我想要一个perl中的方法来做下面的操作示例 xml 文件

<?xml version="1.0"?>
<data>
    <country name="Liechtenstein">
        <rank>1</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/> First Country
    </country>
    <country name="Singapore">
        <rank>4</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/> Second Country
    </country>
    <country name="Panama">
        <rank>68</rank>
        <year>2011</year>
        <gdppc>13600</gdppc>
        <neighbor name="Costa Rica" direction="W"/>
        <neighbor name="Colombia" direction="E"/> Third Country
    </country>
</data>

当我输入元素等级作为输入时，输出应该如下所示。

<?xml version="1.0"?>
    <data>
        <country name="Liechtenstein">
            <rank>1</rank>
        </country>
        <country name="Singapore">
            <rank>4</rank>
        </country>
        <country name="Panama">
            <rank>68</rank>
        </country>
    </data>

Answer 1

此解决方案使用 XML::LibXML ，并通过查找具有所需节点名称的每个 country 元素的子元素，然后删除所有子元素并添加回所选元素来工作。

use strict;
use warnings;

use XML::LibXML;

my $doc = XML::LibXML->load_xml(IO => *DATA, no_blanks => 1);

my $nodename = 'rank';

for my $country ($doc->findnodes('/data/country')) {
  my ($node) = $country->findnodes($nodename);
  $country->removeChildNodes;
  $country->appendChild($node);
}

print $doc->toString(1);

__DATA__
<?xml version="1.0"?>
<data>
    <country name="Liechtenstein">
        <rank>1</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/> First Country
    </country>
    <country name="Singapore">
        <rank>4</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/> Second Country
    </country>
    <country name="Panama">
        <rank>68</rank>
        <year>2011</year>
        <gdppc>13600</gdppc>
        <neighbor name="Costa Rica" direction="W"/>
        <neighbor name="Colombia" direction="E"/> Third Country
    </country>
</data>

输出

<?xml version="1.0"?>
<data>
  <country name="Liechtenstein">
    <rank>1</rank>
  </country>
  <country name="Singapore">
    <rank>4</rank>
  </country>
  <country name="Panama">
    <rank>68</rank>
  </country>
</data>