I would go with something like this

#!/usr/bin/perl
use strict;
use warnings;
use 5.14.0;

my @a1 = qw (a b d e f g);
my @a2 = qw (1 2 3 4 5 6 7);

my $i = 0;
my $count = $#a1 > $#a2 ? $#a1 : $#a2;
for (0 .. $count) {
    no warnings 'uninitialized';
    say "$_: $a1[$_] - $a2[$_]";
}
[download]

Cheers,
R.