On Thu, Jun 9, 2011 at 7:06 PM, Chris Rebert <c...@rebertia.com> wrote: > On Thu, Jun 9, 2011 at 1:31 AM, Ganapathy Subramanium > <sganapathy.subraman...@gmail.com> wrote: >> Hi Guru's, >> I'm working on a solution to find the prime factor of the number >> This part of the code works.. http://www.pastie.org/2041584 > > For the archives, that code is: > > for items in prime_numbers: > if num % items == 0: > prime_factors.append(items) > > print 'The prime factors are : ' , prime_factors
Prime factors don't quite work that way. The prime factors of 24, for instance, are 2, 2, 2, and 3. But if you're looking for _unique_ prime factors, then this will work. Rather than find all prime numbers up to num, stop at sqrt(num) - it's not possible to have any prime factors larger than that. (Be sure to include the square root itself; range(2,sqrt(num)) won't work if num is a perfect square. Use range(2,sqrt(num)+1) for safety.) That will save a fair amount of effort. Also, if you divide num by each factor found, it'll make the numbers smaller, which may be faster. Hope that helps! Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
