ssr1012 ssr1012 - 7 months ago 16
Perl Question

Need the maximum value in label element in list using perl

The below provided list's as contains nested list. I need to fetch the maximum level value in <label> element and insert the value before the <list> element where the attribute appears as 'type="num"'.

For Example:

INPUT:

<list spitype="num" id="list1">
<list-item><label>1</label><para></para></list-item>
<list-item><label>2</label><para></para>
<list spitype="num" id="list1-1">
<list-item><label>1</label><para></para></list-item>
<list-item><label>2</label><para></para></list-item>
<list-item><label>3</label><para></para></list-item>
</list></list-item>
<list-item><label>3</label><para></para></list-item>
<list-item><label>4</label><para></para></list-item>
<list-item><label>5</label><para></para></list-item>
</list>


OUTPUT:

**<max-val-5/>**
<list spitype="num" id="list1">
<list-item><label>1</label><para></para></list-item>
<list-item><label>2</label><para></para>
**<max-val-3/>**
<list spitype="num" id="list1-1">
<list-item><label>1</label><para></para></list-item>
<list-item><label>2</label><para></para></list-item>
<list-item><label>3</label><para></para></list-item>
</list></list-item>
<list-item><label>3</label><para></para></list-item>
<list-item><label>4</label><para></para></list-item>
<list-item><label>5</label><para></para></list-item>
</list>


I have wrote this below code however I didn't get the output. The nested list doesn't not covered on this one. Could you please anyone can help on this will be appreciate.

$incnt=~s{(<list(?: |>)[^>]*>((?:(?!<\/list>).)*)<\/list>)}{
my $list=$1; my ($sbpre,$sbmatch,$sbpost,$slmatch,$LblWidthVal) = "";
if($list=~m/<list(?: |>)[^>]*type="num"[^>]*>/g)
{
$sbpre=$sbpre.$`; $sbmatch=$&; $sbpost=$';
$slmatch=$1 while($list=~m/<label>([^<>]*)<\/label>/sg);
$slmatch=~s/[.,:;\(\)\[\]\{\}]*//g;
$LblWidthVal = "<max-val-$slmatch/>";
$sbmatch = $LblWidthVal."\n".$sbmatch;
$sbpre = $sbpre.$sbmatch; $list = $sbpost;
}
if(length $sbpre) { $list = $sbpre.$sbpost; }
"$list";}igse;

Answer

While it is possible to add a new XML element with a name of max-val-5 it is highly irregular to put information into the name of an element. It's also illegal to have two root elements in an XML element, so I've wrapped your code in a <root>...</root> element and added a new element that looks like `

This solution uses the XML::Twig module, which I think is a little easier to use than XML::LibXML, especially for outputting XML, and has all of its documentation on a single page

I hope you'll agree that it's very straightforward compared with a regex solution

use strict;
use warnings qw/ all FATAL /;

use XML::Twig;
use List::Util 'max';

my $twig = XML::Twig->new( pretty_print => 'indented' );
$twig->parsefile('test.xml');

my $max_label = max $twig->findvalues('//label');

my $max_element = XML::Twig::Elt->new( max => { value => $max_label } );

$max_element->paste( first_child => $twig->root);

$twig->print;

output

<root>
  <max value="5"/>
  <list id="list1" spitype="num">
    <list-item>
      <label>1</label>
      <para></para>
    </list-item>
    <list-item>
      <label>2</label>
      <para></para>
      <list id="list1-1" spitype="num">
        <list-item>
          <label>1</label>
          <para></para>
        </list-item>
        <list-item>
          <label>2</label>
          <para></para>
        </list-item>
        <list-item>
          <label>3</label>
          <para></para>
        </list-item>
      </list>
    </list-item>
    <list-item>
      <label>3</label>
      <para></para>
    </list-item>
    <list-item>
      <label>4</label>
      <para></para>
    </list-item>
    <list-item>
      <label>5</label>
      <para></para>
    </list-item>
  </list>
</root>
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