Find the Level of Sections in XML Structured Document - perl

Question

Find the Level of Sections in XML Structured Document - perl Input:


   ...level 1
   ...level 1
   ...level 1
   
      ...level 2
      ...level 2
      
         ...level 3
         ...level 3
         ...level 3
      
      ...level 2
   
   
      ...level 2
      ...level 2
      ...level 2
   


   ...level 1
   ...level 1
   ...level 1
   
      ...level 2
      ...level 2
      ...level 2
   
   
      ...level 2
      ...level 2
      ...level 2

I need to fetch all the section level elements and insert the value based on the levels. And the desired output like as follows:


...level 1
...level 1
...level 1
   
   ...level 2
   ...level 2
      
      ...level 3
      ...level 3
      ...level 3
      
   ...level 2
   
   
   ...level 2
   ...level 2
   ...level 2
   


...level 1
...level 1
...level 1
   
   ...level 2
   ...level 2
   ...level 2
   
   
   ...level 2
   ...level 2
   ...level 2

First try:

foreach my $lines ( @splitCnt ) {

    if ( $lines =~ m//g ) {
        $opn = $opn - 1;
        $lines =~ s///i;
    }

    $all_lines .= "$lines
";
}

Second Try:

my ( $pre1, $match1, $post1 ) = "";

while ( $incnt =~ m/]*>/g ) {

    $pre1   = $`;
    $match1 = $&;
    $post1  = $';
    my $Opn = '1';
    my $Cls = "";

    $match1 =~ s//i ) {
        $post1 =~ s/



Anyone could help on this one...

Sobrique · Accepted Answer

Seriously - don't use regular expresssions for XML. It's bad news. There's a bunch of perfectly valid things you can do with XML that break regular expressions - so what you get is broken XML, and brittle code that may well break horribly one day, and no one will know quite why.

Use a parser. Personally - I like XML::Twig

It's quite easy to take and rename tags as you ask:

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

use XML::Twig;

sub process_section {
    my ( $section, $depth ) = @_;
    $depth++;
    $section->set_tag("section$depth");
    foreach my $subsection ( $section->children('section') ) {
        process_section( $subsection, $depth );
    }
}

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

foreach my $section ( $twig->findnodes('section') ) {
    process_section( $section, 0 );
}

$twig->print;

I would also point out though - your initial question sounds like an XY problem. What are you trying to accomplish? It's often undesirable to do this sort of operation - changing tags based on hierarchy, because then ... well, then you couldn't do what I've just done - iterate recursively through the data structure.

Find the Level of Sections in XML Structured Document - perl

Answers (2)

output

Related Questions