my @arr = qw( and you will be pleased with the results );
#             0   0   1    0  1       0    1   1
my $mask = 0x2b;

sub mask_array (\@$) {
  my( $arr, $mask ) = @_;
  my @want = split '', unpack( "b*", $mask );
  return @{ $arr }[ grep { $want[ $_ ] } 0..$#{ $arr } ];
}

my @result = mask_array @arr => $mask;

foreach (@result) {
   printf("%s\n", $_);
}

##</code><code>##

my @arr = qw( and you will be pleased with the results );
#             0   0   1    0  1       0    1   1
my $mask = "\x2b";

my @new = do { my $i = 0; map { vec($mask, $#arr - $i++, 1) ? $_ : () } @arr };

foreach (@new) {
   printf("%s\n", $_);
}

##</code><code>##

@arr = qw( and you will be pleased with the results XX YY AA BB );
# \x2b     0   0   1    0  1       0    1   1       0  0  1  0 
# \x2b20   0   0   1    0  0       0    1   0       1  0  1  1
$mask = "\x2b20";

@new = do { my $i = 0; map { vec($mask, $#arr - $i++, 1) ? $_ : () } @arr };

foreach (@new) {
   printf("%s\n", $_);
}