ktsirig

Hi all!
I have this assignment to give in Biology class and I am stuck.

Assignment:
I am given a sequence of letters, say:

XXXXXXABCDXXXXXXXX

and I am interested in part ABCD, which represents letters #7-#10 as you can see.

I am then given the same sequence, which now contains characters like * and !(only these 2 are allowed),
say:

XX**XXX!!!X**AB*!C*DXX*!!!XXX**XXX

and I want to find out which letters now represent the part ABCD.
If you count, you see that ABCD is now letters #14-#20 [4*and! were added prior to A and 10 prior to D]

What I think must be done is:
1) check how many (if any) * or/and ! were added prior to start letter A(#7)
2) check how many (if any) * or/and ! were added prior to end letter D(#10)
3) add all * and/or ! prior to starting and ending letter of part ABCD respectively

Has anyone got any hints to give me as to which functions of Perl will be useful for this problem?

Ooble

Why not just loop through with a "letter counter", start your counting when you hit an A, and reset your counter when you hit something you weren't expecting (not including * or !)?

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Infinite Recursion

Sounds easy enough... maybe if you provided a datafile for an example and a bit more "history" behind the problem and what is expected as the outcome, we could help out more.

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