print " $_ : ".$data->{$_}->{$_}."\n";
[download]

So perl should figure out for you which $_ to use - the one from the inner loop first, then the outer, then the inner?

for (qw(fine)) {
    for (qw(mess)) {
        print "$_ $_\n";
    }
}
__END__
mess mess
[download]

No "fine mess".

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}