in reply to trees of word lists

I'm not sure what you might consider obscure so the following non-recursive code might be either obscure or elegant:

use strict;
use warnings;
use Data::Dump::Streamer;

my @list1 = qw/Truck Car Byke/;
my @list2 = qw/Truck Car Scooter/;
my @list3 = qw/Truck Trailer Skates/;
my %tree;

for my $list (\@list1, \@list2, \@list3, ) {
    my $node = \%tree;
    
    $node = $node->{shift @$list} ||= {} while @$list;
}

Dump \%tree;

[download]

Prints:

$HASH1 = { Truck => {
           Car     => {
                        Byke    => {},
                        Scooter => {}
                      },
           Trailer => { Skates => {} }
         } };

[download]
Perl's payment curve coincides with its learning curve.

Replies are listed 'Best First'.
Re^2: trees of word lists
by lostjimmy (Chaplain) on Jan 22, 2009 at 20:18 UTC

    Every day I realize I have more to learn. Your code is much more elegant than my recursive solution.

    use warnings;
use strict;
use Data::Dumper;

my @lists = ([qw/Truck Car Bike/],
             [qw/Truck Car Scooter/],
             [qw/Truck Trailer Skates/]);

my %tree;

for my $list (@lists) {
    to_tree(\%tree, $list);
}

print Dumper(\%tree);

sub to_tree {
    my ($head, $list) = @_;
    my $node = shift @$list;

    return unless defined $node;

    $head->{$node} ||= {};
    to_tree($head->{$node}, $list);
}

    [download]
[reply]
[d/l]

      I am not even sure I would call your code inelegant. I find it very easy to understand, and very much what I would have written.

      --MidLifeXis

[reply]

In Section Seekers of Perl Wisdom