Hello.

I need some perl REGEX help.

Lets say I have 6 strings as follows:
1. AAA
2. AAABBB
3. AAABBBCC
4. AAABBBCCDDD
5. AAABBBCCDDDE
6. AAABBBFFF

What I want to do is write a perl script that, given a set of strings (like the ones given above for example) it selects the _longest_ string that still contains all of the other preceding strings.

So in this example, the regex should return string #5 since it contains strings 1-4, and then string #6 as a standalone string (strings #1 and #2 were encapsulated by #5 and are not counted again even though they technically appear in #6).

I could do this iteratively with a while-loop (if 2 contains 1 then keep 2; if 3 contains 2 keep 3; etc..) but this is slow for lots of patterns.

I think there might be a regex expression that will do the same thing much faster.
Perhaps there is a perl module that does this.

Can any one help?!
If any of this is unclear please let me know.

Thanks.

Not sure what you mean. Can you provide an example input which, when matched against the RE should extract #5 in your list?

Hi.

Perl function index comes to mind. I don't see that you need to work with regular expressions because all the strings you mentioned are constants, and you appear to be looking for sub-strings in longer strings.

If I understand you, then processing the list above should result in strings 5 and 6 being "unique" in that they are not contained in other strings ... cheers, makyo

( edit 1: clarify )

Thanks for the quick replies!

Actually the example I gave is what the input file looks like:
The lengths of the strings will vary from 10 to 150 alphabetic characters.


makyo: You are correct, the script should return strings 5 and 6 as unique. I'll give the index function a try. Thanks.

I must have a wire crossed - I don't understand your request at all.

You don't have any wires crossed. I'm just terrible at explaining myself.

Sorry about that.

I think the index() idea might work so I'm giving it a test right now.