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emil sanchez
3,089 Pointsquestion on... i ssem to have a correct output but getting a an evaluation as incorrect... requesting for assistance...
You're on fire! Last one and it is, of course, the hardest.
Make a function named reverse_evens that accepts a single iterable as an argument. Return every item in the iterable with an even index...in reverse.
For example, with [1, 2, 3, 4, 5] as the input, the function would return [5, 3, 1].
You can do it!
my code:
list_1 = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19] list_even = [1, 2, 3, 4, 5, 6, 7]
def first_4(list_0): first_list = list_0[:4] return first_list
def first_and_last_4(list_0): first_list = list_0[:4] second_list = list_0[-4:] first_list.extend(second_list) return first_list
def odds(list_0): first_list = list_0[1::2] return first_list
def reverse_evens(list_0): first_list = list_0[::-2] return first_list
list = first_4(list_1) list2 = first_and_last_4(list_1) list3 = odds(list_1) list4 = reverse_evens(list_even)
print(list) print(list2) print(list3) print(list4)
output: [0, 1, 2, 3] [0, 1, 2, 3, 16, 17, 18, 19] [1, 3, 5, 7, 9, 11, 13, 15, 17, 19] [7, 5, 3, 1]
list_1 = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
list_even = [1, 2, 3, 4, 5, 6, 7]
def first_4(list_0):
first_list = list_0[:4]
return first_list
def first_and_last_4(list_0):
first_list = list_0[:4]
second_list = list_0[-4:]
first_list.extend(second_list)
return first_list
def odds(list_0):
first_list = list_0[1::2]
return first_list
def reverse_evens(list_0):
first_list = list_0[::-2]
return first_list
list = first_4(list_1)
list2 = first_and_last_4(list_1)
list3 = odds(list_1)
list4 = reverse_evens(list_even)
print(list)
print(list2)
print(list3)
print(list4)
5 Answers
Kent Åsvang
18,823 PointsI think the problem is that you are returning the evens in reverse without considering the length of the iterable. You should return the even indexes in reverse. (if I have understood the challenge correctly)
To achieve this you just check the length of the list. If the length of the list is an odd number, you can use the slice-method you already have, but if the length of the list is even you have to omit the last item first.
Hope this helped.
emil sanchez
3,089 Pointsit worked.. thanks you very much for your help
Kent Åsvang
18,823 PointsNo worries. Glad to help!
emil sanchez
3,089 Pointsthanks for the help... are you able to solve the quiz?
Kent Åsvang
18,823 PointsYou can try this:
def reverse_evens(iterable):
evens = iterable[0::2]
rev_evens = evens[::-1]
return rev_evens
I do not have access to the challenge so I can't verify it.
Shefeek N
1,303 PointsAnything wrong with this??
def reverse_evens(my_list):
return my_list[0::-2]
Kent Åsvang
18,823 PointsYes. While that function would work if the list has an even numbered length, f.eks:
nlist = [1, 2, 3, 4, 5, 6, 7, 8]
nlist[::-2] # outputs [8, 6, 4, 2]
your function would break down when the length of the list is an odd number:
nlist = [1, 2, 3, 4, 5, 6, 7, 8, 9]
nlist[::-2] # ouputs [9, 7, 5, 3, 1]
the problem occurs because the slicing starts at the end, while you want the evens from the start. Hope that makes sense
Bradley Demerich
11,688 PointsYou should consider the length of the interable.
def reverse_evens(x):
return x[0::2][::-1]
emil sanchez
3,089 Pointsemil sanchez
3,089 Pointsoutput: [0, 1, 2, 3] [0, 1, 2, 3, 16, 17, 18, 19] [1, 3, 5, 7, 9, 11, 13, 15, 17, 19] [7, 5, 3, 1]