use strict;
use warnings;
use Tie::IxHash;

my %myhash;
my %myotherhash;

tie %myhash, 'Tie::IxHash';
for (my $i=0; $i<7; $i++) {
    $myhash{$i} = 2*$i;
}
my @keys = keys %myhash;
print "@keys\n";

for (my $i=0; $i<7; $i++) {
    $myotherhash{$i} = 2*$i;
}
@keys = keys %myotherhash;
print "@keys\n";

__END__
Output:
0 1 2 3 4 5 6
6 4 1 3 0 2 5
[download]

It works in combination with XML::Simple:

use strict;
use warnings;
use Tie::IxHash;
use XML::Simple;

my %myhash;

tie %myhash, 'Tie::IxHash';
$myhash{foo1} = 'bar1';
$myhash{foo3} = 'bar3';
$myhash{foo2} = 'bar2';
$myhash{foo4} = 'bar4';
$myhash{foo5} = [qw(bar5a bar5b bar5c)];

print XMLout(\%myhash, NoSort => 1);
[download]

And the output:

<opt foo1="bar1" foo3="bar3" foo2="bar2" foo4="bar4">
  <foo5>bar5a</foo5>
  <foo5>bar5b</foo5>
  <foo5>bar5c</foo5>
</opt>
[download]

And without the tie:

<opt foo3="bar3" foo4="bar4" foo2="bar2" foo1="bar1">
  <foo5>bar5a</foo5>
  <foo5>bar5b</foo5>
  <foo5>bar5c</foo5>
</opt>
[download]

Alternatively the data could be written with XML::Twig or other XML modules.

Hi Rob, Tying up the hash is done fantastically with the Tie::IxHash module. But when I pass the this tied hash to the XML::Simple it no more follow the tie for the hash. I am trying to get the XML nodes in the sequence which I am following to create the hash elements. Following is the sample code and the output which I am trying to get correct result. If I am missing somewhere please suggest.

use strict;
use XML::Simple;
use Data::Dumper;
use Tie::IxHash;

my     $Request_data = {};

tie my %NewOrder_data , 'Tie::IxHash';

 %NewOrder_data =  (        
                    'IndustryType'        => ['EC'], 
                    'CurrencyCode'        => ['840'],
                    'CurrencyExponent1'    => ['1'],
                    'CurrencyExponent2'    => ['2'],
                    );



my @keys = keys %NewOrder_data;
print "\n@keys\n";

    my $xmlDS = {
        Request => [
                {                
                NewOrder => [
                                {
                                %NewOrder_data,
                                }
                            ],
                    }
            ],
        };



my $request_xml = eval {
    my $xs = new XML::Simple(keeproot => 1, SuppressEmpty => 1);
    $xs->XMLout($xmlDS);
    };

print STDERR "\n\nxml :- >\n" . Dumper($request_xml);


__END__

OUTPUT  :------->


IndustryType CurrencyCode CurrencyExponent1 CurrencyExponent2


xml :- >
<Request>
  <NewOrder1>
    <CurrencyCode>840</CurrencyCode>
    <CurrencyExponent2>2</CurrencyExponent2>
    <IndustryType>EC</IndustryType>
    <CurrencyExponent1>1</CurrencyExponent1>
  </NewOrder1>
</Request>
[download]

Thanks, Sham

For a start, there's one simple change that needs to be made. Replace:

                                {
                                %NewOrder_data,
                                }
[download]

with:

                                \%NewOrder_data,
[download]

Then, at least, $xmlDS will preserve the order that you assigned. (You can verify that with print Dumper($xmlDS), "\n";)

However, the order gets lost in the final step when $request_xml is assigned its value. I couldn't find an easy way to deal with that ... perhaps XML::Simple also needs to 'use Tie::IxHash;' for this approach to work.

Cheers,
Rob