my @pdu_nums = 3 .. 8;
if ( $order ) {
    @pdu_nums = reverse @pdu_nums;
}

# You could check that @nodes >= @pdu_nums here, too.

foreach my $pdu_num ( @pdu_nums ) {
    my $node = shift @nodes;
    unless ( $node ) {
        die "A horrible death!\n";
    }
    $map{ $node} = join '', $pdu, '[', $pdu_num, '}';
}

[download]
Or did I miss something? If I didn't, then the following may also work (and isn't destructive to @nodes). It does assume that the size of @nodes and @pdu_nums is identical and that %map is being created here. 
use List::MoreUtils qw( pairwise );

my @pdu_nums = 3 .. 8;
@pdu_nums = reverse @pdu_nums if $order;

%map = { $b => "${pdu}[${a}]" } pairwise @pdu_nums, @nodes;

[download]
My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

In reply to Re: More effective way to increase two elements of a list in parallel? by dragonchild
in thread More effective way to increase two elements of a list in parallel? by et_alia

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