my $delete  = join '','a'..'z'; # remove all lower case letters
    my $exclude = 'aeiou';          # exluding vowels

    $_ = 'Just Another Perl Hacker';
    s/(?:[$delete](?<![$exclude]))+//g;
    print;

##</code><code>##

    my $delete  = join '','a'..'z'; # remove all lower case letters
    my $exclude = 'aeiou';
    $delete =~ s/[$exclude]+//g;    # excluding vowels

    $_ = 'Just Another Perl Hacker';
    s/[$delete]+//g;
    print;