#!/usr/bin/perl -w 
use strict;
use List::MoreUtils qw(each_array uniq);
use Data::Dumper;

my @ID =       qw(1 1 2 3 4 4 6 6);
my @Values = ([qw(a a a a a a a a )],
              [qw(b b b b b b b b )],
              [qw(c d c c c d c d )]);

print join(" ",uniq @ID), "\n"; #compressed ID's

foreach my $row_ref (@Values)
{ 

  # make hash to gather up values for each ID
  # eg: 1 => [c, d]
  
  my %id2values;
  my $ea = each_array(@ID, @$row_ref);
  while ( my ($id, $value) = $ea->() )   
  { 
     push @{$id2values{$id}}, $value; 
  }
  
  # compress out the dupe values then make a "c/d" string
  # if there is more than one value
  
  my @new = map{join ("/", uniq @{$id2values{$_}})} uniq @ID;
               
  print "@new\n";  #compressed values
}

__END__
1 2 3 4 6
a a a a a
b b b b b
c/d c c c/d c/d


##</code><code>##

Apple Grape Banana
5 2 3/4
10/15 3 4

for:
my @ID =       qw(Apple Apple Grape Banana Banana);
my @Values = ([qw(5 5 2 3 4  )],
              [qw(10 15 3 4 4 )],
              );