my %run_factors = $this_week->get_run_factors();
...
package Week;
...
sub get_run_factots {
  my ($self) = @_;
  my %run_factors;
  @run_factors{$self->active_runs()} = $self->factors();  
}

##</code><code>##

#!/usr/bin/perl -w

use strict;

my @keys = qw(a b c d);
my @values = (1, 2, 3, 4);

my %result = build_hash();

use Data::Dumper;
print STDERR Dumper(\%result);

sub build_hash {
    my %return;

    @return{@keys} = @values;
}


##</code><code>##

$VAR1 = {
          '1' => 2,
          '3' => 4
        };