How can I convert one Perl hash to another using the keys? - perl

Question

I've just started diving in to the crazy world that is perl and have come across a problem that I cannot seem to wrap my head around. Specifically I need to be able to convert from one hash structure to another, that uses the keys/values as the new hashes keys/values.
An example:
Input hash:
my %original_hash = (
first_key => { some_key => "apples",
another_key => "chips",
#potentially more here
},
second_key => { more_of_same => "dogs",
its_another => "cats",
#potentially more here
}
);
Output hash:
my %final_hash = (
some_key => {
apples => {
more_of_same => "dogs",
its_another => "cats",
}
} ,
another_key => {
chips => {
more_of_same => "dogs",
its_another => "cats",
}
}
);
And yes I do want the second_key's data repeated in the final_hash, as there will be an array of the original_hashes that are inputted. The first element becomes the base-case, and all other elements may append or remove from that list.
If anyone has any suggestions on how to go about doing this that would be greatly appreciated!

Answer 1

Here is another way
my %final_hash;
my %tmp = %{$original_hash{first_key}};
my $val = $original_hash{second_key};
while ( my ($k,$v) = each %tmp) {
$final_hash{$k} = { $v => $val };
}
print Dumper (\%final_hash);

Answer 2

Okay, Sinan is right, it's very hard to guess your problem, but the following code seems to do what you want ... or at least it produces the listed output.... :)
use strict;
use warnings;
use Data::Dumper;
$Data::Dumper::Deepcopy = 1;
my %original_hash = (
first_key => { some_key => "apples",
another_key => "chips",
#potentially more here
},
second_key => { more_of_same => "dogs",
its_another => "cats",
#potentially more here
}
);
my %final_hash;
for my $key ( keys %{ $original_hash{first_key} } ) {
$final_hash{$key} = {
$original_hash{first_key}->{$key}
=> $original_hash{second_key}
};
}
print Dumper(\%final_hash);