|Perl: the Markov chain saw|
> I still can't get this to work. I am obviously missing something. So what I want to do is: Use an input DNA sequence and put in array. For each element in array check if the element is a nucleotide. If not a nucleotide print "not a valid character at position xx".
you got everything for this, does it work?
> In the end, print out the number of characters that were valid and the number of characters that were not valid, calculate the percentage of non-valid characters.
That's a new question, you should learn step by step.
> Does this make sense?
Well people answered two very different questions in this thread. You could do better.
Please post your code so far, and try to be clearer what you want.
Most of us here are reluctant to write speculative code if the questions are fuzzy and leave room to various interpretations.