# an array of terms used to create hash1
my @terms = ( 'male','female','child' );

# hash1 of term arrays
my %terms = ();
$terms{1} = [ 'male' ];
$terms{2} = [ 'female' ];
$terms{3} = [ 'child' ];
$terms{4} = [ 'male', 'female' ];
$terms{5} = [ 'male', 'child' ];
$terms{6} = [ 'female', 'child' ];
$terms{7} = [ 'male', 'female', 'child' ];

# hash2 of term occurrences
my %occurs = ();
$occurs{111} = [ 'male' ];
$occurs{112} = [ 'male' ];
$occurs{113} = [ 'male', 'child' ];
$occurs{114} = [ 'female' ];
$occurs{115} = [ 'child', 'female' ];

##</code><code>##

my %tally = ();
# Male on its own appeared twice
$tally{hash1_terms1} = 2;
# Female on its own appeared once
$tally{hash1_terms2} = 1;
# Child on its own appeared twice
$tally{hash1_terms3} = 0;
# and so on...