<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE eSummaryResult PUBLIC "-//NLM//DTD eSummaryResult, 11 May 2002//EN" "http://www.ncbi.nlm.nih.gov/entrez/query/DTD/eSummary_041029.dtd">
<eSummaryResult>

<DocSum>
<Id>29427659</Id>
<Item Name="Caption" Type="String">P81928</Item>
<Item Name="Title" Type="String">RPII140-upstream gene protein</Item>
<Item Name="Extra" Type="String">gi|29427659|sp|P81928|140U_DROME[29427659]</Item>
<Item Name="Gi" Type="Integer">29427659</Item>
<Item Name="CreateDate" Type="String">2003/03/28</Item>
<Item Name="UpdateDate" Type="String">2006/04/04</Item>
<Item Name="Flags" Type="Integer">0</Item>
<Item Name="TaxId" Type="Integer">7227</Item>
<Item Name="Status" Type="String">live</Item>
<Item Name="ReplacedBy" Type="String"></Item>
<Item Name="Comment" Type="String"><![CDATA[  ]]></Item>
</DocSum>


</eSummaryResult>

 my $twig= XML::Twig->new(
               
 TwigHandlers => {
               
     Id => \&id_Tag
               
 }
    );
 

    #actually parse the file
    $twig->parsefile($xml_file) or die "cannot parse [$xml_file]: $!";

    
 
     ###########################################
     sub id_Tag {
     ###########################################
       my($t, $idTag)= @_;

         my $id = $idTag->first_child('Item');
         $idText = $id->{'att'}->{'TaxId'};
           print "TAX_ID: ",$idText,"\n";
       # Release memory of processed tree up to here
    $t->purge();
    }
    

Use of uninitialized value

 my $twig= XML::Twig->new(
  TwigHandlers => {
      item => \&id_Tag
      }
);

###############################
sub id_Tag {
###############################
   my($t, $idTag)= @_;

   return unless($idTag->{att}->{Name} eq 'TaxId');
   $idText = $idTag->text();
   print "TAX_ID: ",$idText,"\n";
   # Release memory of processed tree up to here
   $t->purge();
}