not really, cause it does what you told it to do...

  DB<101> @a = 'a'..'d'
 => ("a", "b", "c", "d")

  DB<102> 'c' =~ /[^@a]/

  DB<103> 'c' =~ /[@a]/
 => 1

  DB<104> $re=qr/[^@a]/
 => qr/[^a b c d]/
[download]

... but wrongly, please note that whitespace is now excluded too!

Apparently you're not showing the whole code.

Are you sure about the content of @aminos?

And why do you exclude 23 letters of the alphabet (in random order) instead of matching the remaining 3?

edit

your array @aminos is empty, thats why /[^]/ tries to exclude ']' within an unterminated character class.

i know what it is.. the @aminos array is empty when the script runs... im starting the script with the command line using getopt::long i declare the array aminos at the first of the script and the other part is in a soubrutine.. so when i call the subroutine with the option sub ... the array @aminos is empty in the subroutine... do you know why is this happening? something like this:

GetOptions ( 'sub' => \&
                  ) 

@aminos= qw (A R N D C Q E G H I L K M F P S T W Y V B Z X);

sub a {
if( "$substr1$substr2" =~ /[^@aminos]/ ) ...
}
[download]

> the @aminos array is empty when the script runs.

yep I just deciphered it from the error msg.

update

> do you know why is this happening?

the initialization of @aminos is never executed.

using strict and warnings might have shown you.

either put the initialization into the sub or declare a constant (string please!).

update

darn, constants are not interpolated in strings or regexes.

you have to define a constant regex:

  DB<131> use constant REGEX=>qr/[^ABCD]/

  DB<132> 'C' =~ REGEX

  DB<133> 'Z' =~ REGEX
 => 1
[download]

Cheers Rolf

( addicted to the Perl Programming Language)

As mentioned before, you're invoking the subroutine (it's invoked during  GetOptions() processing) before the array is initialized. Eg.:

c:\@Work\Perl\monks>perl -wMstrict -le
"S('before');
 ;;
 my @ra = qw(A C T G);
 ;;
 S('after');
 ;;
 sub S { print qq{$_[0] initialization: [@ra] }; }
"
before initialization: []
after initialization: [A C T G]
[download]

/[^\@aminos]/
[download]

Update: Here is the node, as it was when I replied to it:

Hi Monks,
Im getting this error when running my script and i donīt know why

Unmatched [ in regex; marked by <-- HERE in m/[ <-- HERE ^]/ <br/>
[download]

this is the fragment of the code where the error occurs

if( "$substr1$substr2" =~ /[^@aminos]/ )
[download]

any ideas?

why? can you explain?

thats what it should be interpreted.. it is an array with some letters in it