compare multiple hashes for common keys merge values - perl

Question

I have a working bit of code here where I am comparing the keys of six hashes together to find the ones that are common amongst all of them. I then combine the values from each hash into one value in a new hash. What I would like to do is make this scaleable. I would like to be able to easily go from comparing 3 hashes to 100 without having to go back into my code and altering it. Any thoughts on how I would achieve this? The rest of the code already works well for different input amounts, but this is the one part that has me stuck.
my $comparison = List::Compare->new([keys %{$posHashes[0]}], [keys %{$posHashes[1]}], [keys %{$posHashes[2]}], [keys %{$posHashes[3]}], [keys %{$posHashes[4]}], [keys %{$posHashes[5]}]);
my %comboHash;
for ($comparison->get_intersection) {
$comboHash{$_} = ($posHashes[0]{$_} . $posHashes[1]{$_} . $posHashes[2]{$_} . $posHashes[3]{$_} . $posHashes[4]{$_} . $posHashes[5]{$_});
}

Answer 1

my %all;
for my $posHash (#posHashes) {
for my $key (keys(%$posHash)) {
push #{ $all{$key} }, $posHash->{$key};
}
}
my %comboHash;
for my $key (keys(%all)) {
next if #{ $all{$key} } != #posHashes;
$comboHash{$key} = join('', #{ $all{$key} });
}

Answer 2

Just make a subroutine and pass it hash references
my $combination = combine(#posHashes);
sub combine {
my #hashes = #_;
my #keys;
for my $href (#hashes) {
push #keys, keys %$href;
}
# Insert intersection code here..
# .....
my %combo;
for my $href (#hashes) {
for my $key (#intersection) {
$combo{$key} .= $href->{$key};
}
}
return \%combo;
}

Answer 3

Create a subroutine:
sub combine_hashes {
my %result = ();
my #hashes = #_;
my $first = shift #hashes;
for my $element (keys %$first) {
my $count = 0;
for my $href (#hashes) {
$count += (grep {$_ eq $element} (keys %$href));
}
if ($count > $#hashes) {
$result{$element} = $first->{$element};
$result{$element} .= $_->{$element} for #hashes;
}
}
\%result;
}
and call it by:
my %h = %{combine_hashes(\%h1, \%h2, \%h3)};
...or as:
my %h = %{combine_hashes(#posHashes)};

Answer 4

There is pretty straightforward solution:
sub merge {
my $first = shift;
my #hashes = #_;
my %result;
KEY:
for my $key (keys %$first) {
my $accu = $first->{$key};
for my $hash (#hashes) {
next KEY unless exists $hash->{$key};
$accu .= $hash->{$key};
}
$result{$key} = $accu;
}
return \%result;
}
You have to call it with references to hashes and it will return also hash reference e.g.:
my $comboHashRef = merge(#posHashes);