if (@filename = ($_ =~ /$test_regexp/g)) {
    my @complete_urls = map { "http://...." . $_ } @filename;
    ...
}

##</code><code>##

if (@complete_urls = ($_ =~ /$test_regexp/g)) {
    my @filename = map { s{^.*/}{}; $_ } @complete_urls;
    ...
}