#!/usr/bin/perl -w

use strict;
use Data::Dumper;


#  need to split up this array and send three values at a time to
#  sub "do_someting"
my @array = qw( 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 );


while (@array) {

	my @array_segment;

	#  if element isn't defined, don't get the NULL values
    push @array_segment, shift @array;
    push @array_segment, shift @array if defined $array[0];
    push @array_segment, shift @array if defined $array[0];

    do_something(@array_segment);

}

sub do_something {

	my @array = @_;

    print Dumper \@array;

}