perl - How to dig into an certain hash depth? -

i have hash don't know depth. got dbi::selectall_hashref second parameter given user.

so depending on query can have 2-levels hash.

hash_ref = (    aphrodite => (       foo => (          name => aphrodite,          foobar => foo          => 1,          b => 2,       )       bar => (          name => aphrodite,          foobar => bar          => 1,          b => 2,       )    )    apollo => (       ...    )    ares => (       ...    ) ) 

as can see key columns redundant hash. remove redundant keys.

if know 2-levels hash can solve problem this:

for $name (keys $hash_ref) {     $foobar (keys $hash_ref->{$name}) {         $h = $hash_ref->{$name}{$foobar};         delete $h->{name};         delete $h->{foobar};     } }     

however 3-levels hash need 3 cascaded for-loop , on.

how can dynamically remove redundant keys $hash_ref i.e. name , foobar?

my initial idea recursively iterate trough hash:

iterate($hash_ref, scalar @keys); sub iterate {     ($ref, $depth) = @_;     for(keys $ref) {         if ($depth > 0) {              iterate($ref->{$_}, $depth - 1);           }          else {             delete $ref->{$_} for(@keys);         }     } }   

it works it's ugly, ugly... before going further know if missed something. perhaps solution simpler think.

any ideas?

more details?

i writing database fetcher takes user configuration contains sql query $sql , hash keys @keys. values database with:

$dbh->selecthall_hashref($sql, \@keys, {}, @bind); 

i have clean fetched data according additional. apply these rules, have iterate deepest level of $hash_ref access keys/values.

i think need. recurses through hash until finds layer hash values aren't references. removes elements layer keys in @keys

use strict; use warnings; use 5.010;  use data::dump; use list::util 'any';  $hash_ref = {   aphrodite => {     bar => { name => "aphrodite", foobar => "bar", => 3, b => 4, },     foo => { name => "aphrodite", foobar => "foo", => 1, b => 2, },   },   apollo => {     bar => { name => "apollo",    foobar => "bar", => 7, b => 8, },     foo => { name => "apollo",    foobar => "foo", => 5, b => 6, },   },   ares => {     bar => { name => "ares",      foobar => "bar", => 11, b => 12, },     foo => { name => "ares",      foobar => "foo", => 9,  b => 10, },   }, };  @keys = qw/ name foobar /;  remove_dups($hash_ref, \@keys);  dd $hash_ref;  sub remove_dups {   ($href, $keys) = @_;   if ( { ref } values %$href ) {     remove_dups($_, $keys) values %$href;   }   else {     delete @{$href}{@$keys};   } } 

output

{   aphrodite => { bar => { => 3, b => 4 }, foo => { => 1, b => 2 } },   apollo => { bar => { => 7, b => 8 }, foo => { => 5, b => 6 } },   ares => { bar => { => 11, b => 12 }, foo => { => 9, b => 10 } }, }