Re: map into a multidimensional hash

[Eily]

Same as Discipulus++, I get the same output in both cases. Edit: that's because the map version is incorrect when an id_1 is repeated for distinct id_2, which the AoH that I constructed fails to demonstrate (as pointed out by choroba).

For me, the clever way to do it would be one that is easy to read, so I'd go for a for loop rather than map

If you are searching for new/unusual ways to do thing you can use postfix dereferencement to get the two values in one go:

use feature 'postderef'; # Needed in perl 5.20 and 5.22

my @aoh = (
            { id_1 => "F1", id_2 => "F2", v => "FV" },
            { id_1 => "S1", id_2 => "S2", v => "SV" },
            { id_1 => "T1", id_2 => "T2", v => "TV" },
          );

my %hash;
foreach my $href (@aoh)
{
  my ($id_1, $id_2) = delete $href->@{'id_1', 'id_2'};
  $hash{$id_1}{$id_2} = $href;
}

But if you want to do the construction in two lines (you still have to declare the output hash), you can use the postfix version of for

my %hash;
$hash{delete $_->{id_1}}{delete $_->{id_2}} = $_ for @aoh;

Edit: postfix deref is only available since perl v5.20, and the explicit use of the feature is required up to v5.22

Edit: s/[@]ao\Kf/h/; Thanks johngg