Wolfgang Maier wrote: > Dear all, with > a=list(range(1,11)) > > why (in Python 2.7 and 3.3) is this explicit for loop working: > for i in a[:-1]: > a.pop() and a > > giving: > [1, 2, 3, 4, 5, 6, 7, 8, 9] > [1, 2, 3, 4, 5, 6, 7, 8] > [1, 2, 3, 4, 5, 6, 7] > [1, 2, 3, 4, 5, 6] > [1, 2, 3, 4, 5] > [1, 2, 3, 4] > [1, 2, 3] > [1, 2] > [1]
No. Introduce a result list, and you'll see that you append the *same* list to the result nine times: >>> a = range(1, 11) >>> result = [] >>> for i in a[:-1]: ... result.append(a.pop() and a) ... >>> result [[1], [1], [1], [1], [1], [1], [1], [1], [1]] > but the equivalent comprehension failing: > [a.pop() and a for i in a[:-1]] > > giving: > [[1], [1], [1], [1], [1], [1], [1], [1], [1]] > > ??? > Especially, since these two things *do* work as expected: > [a.pop() and a[:] for i in a[:-1]] > [a.pop() and print(a) for i in a[:-1]] # Python 3 only So you already know the solution to your problem... -- http://mail.python.org/mailman/listinfo/python-list
