in reply to Add new elements with XML::Simple

What you have is a pretty specific solution, and as such, is really only useful for you. But, you can indeed trim the code down. Here is one to do that: 

use strict;
use warnings;
use XML::Simple;
use Data::Dumper;
 
my $data = XMLin(\*DATA, ForceArray => 1);
 
for my $trans (@{ $data->{trans} }) {
    next unless $trans->{kool} eq 'max';
    $trans->{item} = [$trans->{item}] unless ref $trans->{item} eq 'AR
+RAY';
 
    push @{ $trans->{item} }, {
        maxis => { assignee => ['jill'], status => ['con'] }
    };
}
 
print XMLout($data, KeyAttr => 'id');
 
__DATA__
<opt>
 <trans kool="max">
  <item id="legas">
    <status>contacted</status>
    <assignee>jack</assignee>
  </item>
 </trans>
 <trans kool ="kool">
  <item id="gas">
    <status>contacted</status>
    <assignee>jack</assignee>
  </item>
 </trans>
</opt>

[download]

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

Replies are listed 'Best First'.
Re^2: Add new elements with XML::Simple
by Maxim (Sexton) on Oct 13, 2004 at 21:26 UTC
    Thanks Jeffa for your other way to trim the code down. I think, I have a problem because how do I know "trans" is the last one of my XML file.

    For example I have in this XML file, the last "trans" is kool: 
    <opt>
 <trans kool="max">
  <item id="legas">
    <status>contacted</status>
    <assignee>jack</assignee>
  </item>
 </trans>
 <trans kool="sss">
  <item id="legas">
    <status>contacted</status>
    <assignee>jack</assignee>
  </item>
 </trans>
 <trans kool ="kool">
  <item id="gas">
    <status>contacted</status>
    <assignee>jack</assignee>
  </item>
 </trans>
</opt>

    [download]

    I think I need to use a loop with a counter. What do you think Jeffa?

    Maxim
[reply]
[d/l]

      First, you hardly ever need an extra counter when you loop in Perl. That is a hold over from other languages, i had the same bad habit myself when i started Perl. Second, since you know which <trans> you want, the one with kool="kool", then you don't need to worry about counting them: just "ask" for the <trans> tag with attribute kool that is set to "kool". Third, use the right tool for the right job. In this case, XML::Twig is the Vorpal Blade you seek: 

      use strict;
use warnings;
use XML::Twig;
 
my $twig = XML::Twig->new(pretty_print => 'indented');
my $data = do {local $/;<DATA>};
$twig->parse($data);
 
my $root  = $twig->root;
my @trans = $root->children;
 
for my $trans (@trans) {
    next unless $trans->att('kool') eq 'kool';
 
    my $item = XML::Twig::Elt->new(item => { id => 'maxis'});
 
    my $assignee = XML::Twig::Elt->new(assignee => 'Jill')
        ->paste(last_child => $item);
 
    my $status = XML::Twig::Elt->new(status => 'con')
        ->paste(last_child => $item);
 
    $item->paste(last_child => $trans);
}
 
$twig->print;
 
__DATA__
<opt>
 <trans kool="max">
  <item id="legas">
    <status>contacted</status>
    <assignee>jack</assignee>
  </item>
 </trans>
 <trans kool ="kool">
  <item id="gas">
    <status>contacted</status>
    <assignee>jack</assignee>
  </item>
 </trans>
</opt>

      [download]
      See? No need for an extraneous counter, the next unless $trans->att('kool') eq 'kool'; line will skip all <trans> tags that do not have an attribute named kool set to "kool".

      jeffa

      L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)
[reply]
[d/l]
        I see now. Also I am a new in Perl, so I have the same problem as you before. I understand when using the  next unless $trans->att('kool') eq 'kool'; it is easy to do it instead to have a counter.
        Thanks for your advise. I really appreciated.

        Maxim
[reply]
[d/l]

In Section Seekers of Perl Wisdom