Somehow the idea to “parse” a XML file with a regexp keeps popping up. In general this is not the way. Use a XML parser for this job! There are several alternatives, see CPAN:-)

In case of the suggested XML::Twig you could use an XPath expression to filter out the people you’re looking for. Or go over all of them and test for the age element to have a text value of 43.

Update:
Something like (going over all people): 

use strict;
use warnings;
use XML::Twig;

# Usage of finish_print
my $twig= new XML::Twig( 
                twig_roots =>                  
                  { 'name' => \&name }
                       );  
$twig->set_pretty_print ('nsgmls'); # Human readable output please
$twig->parsefile( "some_file_name.xml");             

sub Name { 

    my( $twig, $name)= @_;
    $name = $name->first_child("First");
    
    if ($name->text eq "43") {
        
        # Do stuff
        
    } else {
            
    }
}

[download]
Untested as you don't provide the exact structure of the XML file.

Update 2
Fixed typo's

In reply to Re: I want to find a group of pattern in a xml file by dHarry
in thread I want to find a group of pattern in a xml file by cybär

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