If I am searching for 2 sequences within the same haystack, and what separates the 2 sequences is always a "T" followed by one other nucleotide (either A,G,C,or T),

Could you explain that a bit more?

I get that you are looking for ???...????T[acgt]???..???; but that criteria will match everywhere a T occurs in a sequence, other than if it is the first, or second or third last, characters in the sequence. And without some constraints on the lengths of the pre & post T sequence length, there would be multiple (100s or 1000s or millions) possible matches at every T position.

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In reply to Re^11: Comparing 2 different-sized strings by BrowserUk
in thread Comparing 2 different-sized strings by AdrianJ217

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