So I guess all that means that you avoid do { } blocks as well? After all, you can't put an explicit return in there either. Pity, you're missing out on a great tool to clarify and structure code. You'll find stuff like this all over my code:

my $timestamp = {
    my( $year, $month, $date ) = ( localtime )[ 5, 4, 3 ];
    $year += 1900;
    $month++;
    join '-', $year, $month, $date;
};
[download]

No leaked variables. Also trivial to refactor into a sub if I notice I need it more than once.

And if variable names are so important (yes, they are), what's that $hash doing there in your code?

In any case,

my @newLoop = map +{
    PARTNAME => $_,
    SELECTED => $_ eq $row->{ title },
}, @$parts;
[download]

(No, it doesn't cost much extra memory. The base memory overhead of an anonymous hash is so large it easily overshadows an empty key. I'd build this structure inside-out by saying { SELECTED => 42, PARTS => [ 'foo', 'bar', 'baz', ... ] }, which takes a fraction of the memory and also makes updating the selected entry an atomic O(1) vs a two-step O(n) operation, but that's just me.)