On 8/19/2010 2:41 PM, Thomas Jollans wrote:
On Thursday 19 August 2010, it occurred to Baba to exclaim:
This is not recursive. In fact, it's exactly the same approach as the first one, plus a bit of an if statement.
Right. The original poster seems to be getting their ideas from "http://stackoverflow.com/questions/2308696/substring-recursive-algorithm-not-working"; which is a rather confused article, or http://talkbinary.com/programming/c/c-recursion-palindrome/ which really has a recursive, although inefficient, example. If you're really interested in this area, read up on the Boyer-Moore Fast String Search Algorithm, which is the fast way to do this for long strings. For Python, a quick solution is def countSubStringMatch(target, key) : esckey = re.sub(r'(\W)',r'\\\1',key) # put \ escapes into key cnt = len(re.findall(esckey, target)) # find all key and count print('%s is %d times in the target string' %(key,cnt)) >>> countSubStringMatch("atgacatgcacaagtatgcat","ca") ca is 4 times in the target string Enjoy. John Nagle -- http://mail.python.org/mailman/listinfo/python-list
