XmlSimpleHash.pl - XML Hash Example

Perl Tutorials - Herong's Tutorial Examples

∟XML::Simple Module - XML Parser and Generator

∟XmlSimpleHash.pl - XML Hash Example

This section provides a tutorial example on how to work with hashes resulted from the XML::Simple parsing operation, XMLin().

The following example shows you how to modify the resulting hash of the parsing operation. The important thing to remember when accessing the contents of the hash is that everything is parsed as array or hash. Hashes hold the tag names and attributes, and arrays hold their content.

#- XmlSimpleHash.pl
#- Copyright (c) HerongYang.com. All Rights Reserved.
#
   use XML::Simple;
   use Data::Dumper;
   my $xs = new XML::Simple(keeproot => 1,searchpath => ".",
      forcearray => 1, suppressempty => '');
   my $ref = $xs->XMLin("system.xml");
   my $xml = $xs->XMLout($ref);
   print "\nHash dump:\n";
   print Dumper($ref);
   print "\nXML output:\n";
   print $xml;
   $ref->{system}->[0]->{user}->[1]->{first_name}->[0] = "Bill";
   $ref->{system}->[0]->{user}->[1]->{email}->[0] = "bill\@wong.com";
   my $xml = $xs->XMLout($ref);
   print "\nUpdated XML output:\n";
   print $xml;
   exit;

Output:

Hash dump:
$VAR1 = {
          'system' => [
                        {
                          'content' => [
                                         '
 This is a testing system.
 ',
                                         '
 Needs to add more entries later.
'
                                       ],
                          'user' => [
                                      {
                                        'first_name' => [
                                                          'Mike'
                                                        ],
                                        'status' => 'active',
                                        'last_name' => [
                                                         'Lee'
                                                       ],
                                        'email' => [
                                                     'mike@lee.com'
                                                   ]
                                      },
                                      {
                                        'first_name' => [
                                                          ''
                                                        ],
                                        'last_name' => [
                                                         'Wong'
                                                       ],
                                        'content' => '
  Missing first name and email.
  ',
                                        'email' => [
                                                     ''
                                                   ]
                                      }
                                    ]
                        }
                      ]
        };

XML output:
<system>
  <content>
 This is a testing system.
 </content>
  <content>
 Needs to add more entries later.
</content>
  <user status="active">
    <first_name>Mike</first_name>
    <last_name>Lee</last_name>
    <email>mike@lee.com</email>
  </user>
  <user>
  Missing first name and email.
  <first_name></first_name>
    <last_name>Wong</last_name>
    <email></email>
  </user>
</system>

Updated XML output:
<system>
  <content>
 This is a testing system.
 </content>
  <content>
 Needs to add more entries later.
</content>
  <user status="active">
    <first_name>Mike</first_name>
    <last_name>Lee</last_name>
    <email>mike@lee.com</email>
  </user>
  <user>
  Missing first name and email.
  <first_name>Bill</first_name>
    <last_name>Wong</last_name>
    <email>bill@wong.com</email>
  </user>
</system>