Perl processing of an XML file

Same <primary_id> as what? Same as "BRMNTN62M16A944E"
What characters are allowed <first_name> and <last_name>?

Hi, ozo
yes: same as "BRMNTN62M16A944E".
i.e. there're 2 records with
1) same <primary_id>BRMNTN62M16A944E</primary_id>

2) same first & second, say:
<first_name>John</first_name>
<last_name>Doe</last_name>

3) but different email, say:
<user_identifier>
<id_type desc="Additional">02</id_type>
<value>john.doe@mymail.com</value>
</user_identifier>

for the first record and

<user_identifier>
<id_type desc="Additional">02</id_type>
<value>something.else@mymail.com</value>
</user_identifier>

I want to keep only the first <user>...</user> record and delete the second
Thanks a lot,
Fabiano

Hi, ozo
to make the things more clearer (I hope) I've attached a sample file with 2 <user> records.
They have the same value for the fields:
<primary_id>BRMNTN62M16A944E</primary_id>
<first_name>john</first_name>
<last_name>doe</last_name>

but different value in the user_identifier field.
for the first record:
<user_identifier>
<id_type desc="Additional">02</id_type>
<value>john.doe@uniud.it</value>
</user_identifier>

and for the second one:

<user_identifier>
<id_type desc="Additional">02</id_type>
<value>someOther.thing@uniud.it</value>
</user_identifier>

I want to keep only the first <user> record and delete the second.
Thanks,
Fabiano
sample.xml

You need to parse your XML with a Perl module which gives you access to all its elements, in a hierarchy that you can use to find whatever you want and delete it.   I generally use XML::LibXML for this.  Here's a little bit of code that may help you get going; XML::LibXML and its related modules (XML::LibXML::Node and XML::LibXML::Element are the ones you'll use most) will do everything you want.

#!/usr/bin/perl
use strict;
use warnings;
use 5.010;
use XML::LibXML;

my $dom = XML::LibXML->load_xml(location => 'sample.xml');

my @primary_ids = $dom->findnodes('/users/user/primary_id');

my $previous_id = '';
foreach my $id_elt ( @primary_ids ){
    my $this_id = $id_elt->to_literal();
    if ( $this_id eq $previous_id ){
	my @user_identifiers = $id_elt->parentNode()->findnodes('./user_identifiers/user_identifier');
	print "User identifiers for $this_id: \n";
	print "-----------------\n$_\n" for @user_identifiers;
        print "Here you do other things as required\n";
    }
    else {
	$previous_id = $this_id;
    }
}

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Hi, Thanks a lot for the reply
is this work possible with the XML::Simple module?
Thanks,
Fabiano

You could try, but i personally wouldn't recommend it.  XML::Simple makes assumptions about the way that the XML data is represented by variables--arrays, hashes and so forth--which may not be the best way of doing it from the programming point of view.  There are parameters that you can pass which change that, but the way the arrays and hashes are created has a tendency to change with the structure of the data, so that your program may fail at some later stage because perfectly valid XML is structured in a new way.  The CPAN entry for XML::Simple even says this: "The use of this module in new code is discouraged. Other modules are available which provide more straightforward and consistent interfaces"

If you know XML::Simple then this page may be of interest.

Hi,
Thanks for the reply.
I use W7 with activeperl 5.24.0 and on the ppm I can find the XML::Simple and XML::Parser modules, but sadly not the XML::LibXML module

Hi, Henry
Thanks: I'll follow your suggestions
Thanks,
Fabiano