Antoon Pardon wrote: > Suppose I have a list with 10 000 elements and I want > the sum of the first 100, the sum of the second 100 ... > > One way to do that would be: > > for i in xrange(0,10000,100): > sum(itertools.islice(lst, i, i+100)) > > But itertools.islice would each time start from the begining > of the list and iterate over i elements before giving 100 > elements to sum. Which would make this implementation O(n^2) > instead of O(n). Can you use iter for this situation ?
a=iter(lst) for i in xrange(0,10000,100): sum(itertools.islice(a,100)) -- http://mail.python.org/mailman/listinfo/python-list
