[EMAIL PROTECTED] wrote: > I'm creating a program to calculate all primes numbers in a range of 0 > to n, where n is whatever the user wants it to be. I've worked out the > algorithm and it works perfectly and is pretty fast, but the one thing > seriously slowing down the program is the following code: > > def rmlist(original, deletions): > return [i for i in original if i not in deletions] > > original will be a list of odd numbers and deletions will be numbers > that are not prime, thus this code will return all items in original > that are not in deletions. For n > 100,000 or so, the program takes a > very long time to run, whereas it's fine for numbers up to 10,000. > > Does anybody know a faster way to do this? (finding the difference all > items in list a that are not in list b)?
- Make deletions a set, testing for membership in a set is much faster than searching a large list. - Find a better algorithm ;) Kent -- http://mail.python.org/mailman/listinfo/python-list
