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Python Python Collections (2016, retired 2019) Slices Slice Functions

Rafael Quintero
Rafael Quintero
9,935 Points

reverse_evens function

Don't know why my function isn't working. I ran it using the terminal in my mac and the output was exactly what I needed, but when I pasted it to the challenge, it says that it's not getting the right output.

def first_4(iterable):
    return iterable[:4]

def first_and_last_4(iterable):
    return iterable[:4] + iterable[-4:]

def odds(iterable):
    return iterable[1::2]

def reverse_evens(iterable):
    return iterable[::-2]

1 Answer

Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

You are close. Keep in mind that the iterable passed in might have an odd number or even number of items. Simply taking every other item from the back of the list does not work if there is an even number of items:

>>> [1,2,3,4,5][::-2]
[5, 3, 1]
>>> [1,2,3,4,5,6][::-2]
[6, 4, 2]

Hint: First capture the even indexed items, then reverse this to get the final return value

Post back if you need more help. Good luck!!