use Data::Dumper;

use strict;
use warnings;

my $file = "afile";
my $alias = "somealias";
my %num;
my %val;
$num{$alias}{save} = 2;
$val{$file}[3][$num{$alias}{save}] = 1;
print Dumper(\%val);

##</code><code>##

$VAR1 = {
          'afile' => [
                       undef,
                       undef,
                       undef,
                       [
                         undef,
                         undef,
                         1
                       ]
                     ]
        };