my $scan = [0,qr/a/,2,qr/C/];
my @filtered = grep scan $scan,
             @$table
sub scan {
    my $aref = shift;
    my $i    = 0;
    while( ++$i < @$aref ){
        return unless $_->[$i-1] =~
                $aref->[$i++]
    }
    1
}