On 9 May 2018, at 23:57, Rick Jaramillo <rck.le...@gmail.com> wrote:
> >Hello, >I’m having trouble understanding the following behavior and would greatly >appreciate any insight. >l = [1,2,3,4] >b=[] >for i in range(l): > print l > b.append(l) > l.pop(0) >print b >OUTPUT >[1,2,3,4] >[2,3,4] >[3,4] >[4] >[[],[],[],[]] >My confusions is the output for b. I don’t understand why it’s empty. I’m >expecting for b to equal [[1,2,3,4], [2,3,4], [3,4], [4]]. You append l each time. The same l, not a copy of its current state. You also modify l each time. But there is only one list object. It is just being referenced from several places. So all of the references reflect your changes. Alan g _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
