#!/usr/bin/perl --
use strict; use warnings;
use Data::Dump;
use XML::TreeBuilder;

my $tree = XML::TreeBuilder->new();
$tree->parse(<<'__XML__');
<drug type="small molecule">
  <name>Goserelin</name>
  <targets>
    <target partner="1">
      <known-action>yes</known-action>
    </target>
    <target partner="2">
      <known-action>yes</known-action>
    </target>
    <target partner="3">
      <known-action>yes</known-action>
    </target>
  </targets>
</drug>
__XML__


foreach my $drug ( $tree->find_by_tag_name('drug') ) {
    
    my @targets = $drug->look_down( '_tag', 'target' );
    for my $target ( @targets ){
        print $target->attr('partner'), "\t";
    }

    print "\n";
    
    my @act = $drug->look_down( '_tag', 'known-action' );
    @act = map { $_->as_trimmed_text } @act;
    
    print join "\t", @act, "\n";
    
}