I have voted only for your solution. Because while everyone is showing solutions with sort, map grep. I just don't understand that after 30 posts finally someone is talking some sense.

If I would have needed to solve something like this, I would have come up with a simple loop. Job done, move on:

use strict ;
use warnings ;

my @arr = ( 3, 4, 71, 1, 1.5, -598, -100203, 0.5, -2, -1.5 );

my $result ;
while (my ($ix, $val) = each @arr) {
    next if ( $val < 0 || int $val != $val || ($result && $val > $resu
+lt->[0]) ) ;
    $result = [ $val, $ix ] ;
}
if ( $result ) {
    print $result->[0] . " at " . $result->[1] . "\n" ;
}
__END__
1 at 3
[download]