in reply to How to transform a matrix into a hash??

IMO, Data::Diver is definitely the way to go here. No fuss, no muss - just DWIMery. 

use strict;
use warnings;

use Data::Diver qw( DiveVal );
use Data::Dumper;

my $aokeys =
    [
        [ 'a', 'b', 'c' ],
        [ 'a', 'b', 'd' ],
        [ 'b', 'b', 'b' ],
    ];

my $href = {};

foreach my $key_aref ( @$aokeys )
{
    DiveVal( $href, @$key_aref ) = 1;
}

print Dumper $href;

[download]
$VAR1 = {
          'a' => {
                   'b' => {
                            'c' => 1,
                            'd' => 1
                          }
                 },
          'b' => {
                   'b' => {
                            'b' => 1
                          }
                 }
        };

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Re^2: How to transform a matrix into a hash??
by yocoim (Initiate) on Feb 06, 2008 at 19:47 UTC
    Thanks all for your suggestions!
    I never used 'eval', but from what I've read, it seems like a good thing!
    The recursive way of doing it has nothing wrong, but I was wondering if there were other ways - to learn new tricks :)
    Thanks again! Maybe I can actually post the recursive way: 
    
my @array_2D = blablabla
my ($tree, $tmp);

foreach my $row (@array){
    $tmp = extend_MTree($row);
    $tree = add($tmp, $tree);
}

$tree now contains the hash!

sub extend_MTree($)
  {
    my ($a) = @_;

    my %H_tmp;

    if( $#{$a} == -1)
      {
    return 1;
      }

    my $elmt = shift @$a;
    $H_tmp{$elmt} = extend_MTree($a);
    return \%H_tmp;
  }

sub add()
  {

    my ($tmp, $res) = @_;

    foreach my $key (keys %$tmp)
      {

    # this is a new path, add here and leave
    if(!defined($res->{$key}))
      {
        $res->{$key} = $tmp->{$key};
        return $res;
      }

    # this part of the path exists, recurse
    $res->{$key} = add($tmp->{$key}, $res->{$key});
    return $res;
      }

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