#! /usr/bin/perl
# vim:ts=4 sw=4 sts=4 et nu fdc=3:
use strict;
use warnings;

use Data::Dumper;
$Data::Dumper::Sortkeys = 1;

# data structure: Hash of Arrays
# Device => [ list of vlan IDs ]
my %vlan = (
    device_1 => [ 1..38 ],
    device_2 => [ 1..48 ],
    device_3 => [ 1..24 ],
);



sub fetch_data {
    my $hRef = shift;
    my %data;

    for my $dev ( keys %$hRef ) {
        # skip if no vlan IDs left for current device
        next if 0 == @{ $vlan{$dev} };

        # extract next 10 IDs of current device
        $data{$dev} = [ splice( @{$vlan{$dev}}, 0, 10 ) ];
    }

    return %data;
}


# take 10 items of each device sub hash:  via fetch_data()
# process items:  print Dumper( \%data )
# redo until all sub hashs are empty
while ( my %data = fetch_data( \%vlan ) ) {
    print Dumper( \%data );
}

__END__