data structures - Efficient way of printing hash of hash of arrays in Perl -

i writing script involves printing contents of hash of hash of arrays.

ex (pseudo code):

my %hash = (); $hash{key1}{key2} = ['value1', 'value2', 'value3', . . .]; 

or

$hash{key1}{key2} = @array_of_values; 

basically want able number of key combinations , able loop through of possible key/value pairs (or more correctly stated key,key/array pairs since each value array of values , each array has 2 keys associated it) , print output in following format:

"key1, key2, value1, value2, value3, . . .\n"

ex:

#!/usr/bin/perl  use strict; use warnings;  # initialize hash %hash = (); $string1 = "string1"; $string2 = "string2";  # push strings onto arrays stored in hash push @{$hash{a}{b}}, $string1; push @{$hash{a}{b}}, $string2; push @{$hash{c}{d}}, $string2; push @{$hash{c}{d}}, $string1;  # print elements of hash # (want loop possible key/value pairs) local $, = ','; print "a, b, "; print @{$hash{a}{b}}; print "\n"; print "c, d, "; print @{$hash{c}{d}}; print "\n";  system ('pause'); 

the output code shown below:

a, b, string1,string2 c, d, string2,string1 press key continue . . . 

i thinking using each operator appears work 1 dimensional hashes. (each returns 1 key value pair, not work correctly when there 2 keys involved)

how can streamline code traverse through hash in loop , print desired output regardless of how big hash gets?

sounds need nested loop ... there's way map harder remember , less readable ;-) (speaking myself of course - forward seeing map solution appear here!):

#!perl -l %hash = (); $hash{key1}{key2} = ['value1', 'value2', 'value3',];  $outer (keys %hash) {      $inner (keys $hash{$outer}) {         print join(', ', $outer, $inner, @{ $hash{$outer}{$inner} } )     }  } 

output:

key1, key2, value1, value2, value3 

there's data::printer, data::seek,data::dive , several other convenience modules if things complicated. require use of hash references though may complicate simpler solution or make larger , more difficult problem more possible ...

cheers,

edit: moved "nested map" separate answer.