Billy Mays wrote:
Is xrange not a generator? I know it doesn't return a tuple or list, so what exactly is it? Y doesn't ever complete, but x does.
range(n) creates a list containing all the integers 0..n-1. This is a problem if you do range(1000000), because you'll end up with a >4Mb list. xrange deals with this by returning an object that pretends to be a list, but just works out the number needed from the index asked for, and returns that.
range() can actually be faster in some cases - eg. if iterating over the same sequence multiple times. xrange has to reconstruct the integer object every time, but range will have real integer objects. (It will always perform worse in terms of memory however)
xrange isn't usable in all cases where a real list is needed. For instance, it doesn't support slices, or any list methods.
-- m harris FSF ...free as in freedom/ http://webpages.charter.net/harrismh777/gnulinux/gnulinux.htm -- http://mail.python.org/mailman/listinfo/python-list
