in reply to XML parsing

I haven't had to do anything with XML that I couldn't get done with XML::Twig. May $DEITY bless mirod.

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Re^2: XML parsing
by mading0 (Initiate) on Oct 03, 2014 at 17:26 UTC
    Perhaps you can help me with Twig, then. What I want to do is search within a parent node for a specific text content of an element. If it doesnt match the string, then delete the entire parent node. Here's an example: 
    <book>
 <book1>Book1</book1>
  <title>Title of Book 1</title>
   <genre>Fantasy</genre>
</book>

    [download]
    What I'd like to do in this case is search within each <book> and see if the title matches "Title of Book 1". If it doesn't, I want that entire <book> deleted. Does this make sense?
[reply]
[d/l]

      See the section "Building an XML filter" of XML::Twig. Here's a quick implementation:

      use XML::Twig;
open my $ofh, '>', $output_filename or die $!;
XML::Twig->new(
  twig_print_outside_roots => $ofh,
  keep_spaces => 1,
  twig_roots => {
    book => sub {
      my ($twig, $book) = @_;
      if ($book->first_child_text('title') eq 'Title of Book 1') {
        $book->flush($ofh);
      }
      else {
        $book->purge;
      }
      return 1;
    }
  },
)->parsefile($input_filename);
close $ofh;

      [download]
[reply]
[d/l]
      I would say that your example is probably over simplistic, so I've expanded on and cleaned it up slightly: 
      <library>
 <book>
  <book1>Book1</book1>
  <title>Title of Book 1</title>
  <genre>Fantasy</genre>
 </book>
 <book>
  <book2>Book2</book2>
  <title>Not the Title of Book 1</title>
  <genre>Fantasy</genre>
 </book>
</library>

      [download]

      Now that we have something that's a little bit easier to show off some stuff, here's an example that does exactly what you ask. 
      use strict;
use warnings;
use XML::Twig;
use Data::Dumper;
my $DATA = '
<library>
 <book>
  <book1>Book1</book1>
  <title>Title of Book 1</title>
  <genre>Fantasy</genre>
 </book>
 <book>
  <book2>Book2</book2>
  <title>Not the Title of Book 1</title>
  <genre>Fantasy</genre>
 </book>
</library>
';

my $source_twig = XML::Twig->new('pretty_print' => 'indented');
$source_twig->safe_parse($DATA);

foreach my $book ($source_twig->root->children('book')) {
  if ($book->first_child('title')->text() ne 'Title of Book 1') {
    $book->cut()
  }
}
$source_twig->print();

      [download]

      And it's output: 
      <library>
  <book>
    <book1>Book1</book1>
    <title>Title of Book 1</title>
    <genre>Fantasy</genre>
  </book>
</library>

      [download]
[reply]
[d/l]
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