Those methods of computing partial sums seem to be O(n^2) or worse. What's wrong with an ordinary loop?
for i in xrange(1, len(l)): l[i] += l[i - 1] And as for the list of objects: ll = [l[i - 1].method(l[i]) for i in xrange(1, len(l))] + l[-1] -- http://mail.python.org/mailman/listinfo/python-list