"Ishwor" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > On Sun, 26 Dec 2004 04:57:17 -0500, Terry Reedy <[EMAIL PROTECTED]> wrote: >> >> "Ishwor" <[EMAIL PROTECTED]> wrote in message >> news:[EMAIL PROTECTED] >> > Hi all >> > I have just wrote a small script to compare the speed of list addition >> > methods. >> >> There are two meanings of 'list addition': >> >> li = li+[item] *copies* the list and adds item >> >> li += [item] is the same as li.extend([item]) which add item to the end >> of >> the list *without* copying. >> >> Of course, extending a list is faster than copying + one more. >> > > I agree with you that list extending is faster way to add as compared > to method 1. also that method 2 is mapped to 'extend()' anyway,
As near as I could tell from what you posted (and I snipped), method 2 was about the same as 1 and not mapped to extend(). > but > why is the method 3 ( l3.extend() ) in my example code talking only > nearly 1% of time to complete as compared to method 1/2??? Because writing 1 pointer takes 1/100th as long as writing 100 pointers (in the C code of CPython). You used lists long enough for the difference between O(n) and O(n**2) behavior to show. > Thanks Terry for yet another small (really small) step towards > enlightment. You're welcome. Hope this is another small step ;-) Terry J. Reedy -- http://mail.python.org/mailman/listinfo/python-list
