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

igor corrales
igor corrales
2,474 Points

I think I don't understand challenge 4 of 4

My problem is this sentence :

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].

Because I did what the sentence ask for in my code but the program give me this:

"Don't get the right results"

slices.py
def first_4(rango1):
    f = rango1[0:4]
    return f

def first_and_last_4(rango):
        b = rango[0:4]
        c = rango[-4:]
        d = b + c
        return d

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

def reverse_evens(rango4):
        a = rango4[-1::-2]
        return a

1 Answer

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there, igor corrales! I think you do understand what the challenge wants just fine and your code does work but only in half the cases. Your code works when the number of items in the iterable is an odd number. If I sent in [1, 2, 3, 4, 5, 6] to your code, I would expect to still get back [5, 3, 1] because those are the items in the iterable at even indexes and then in reverse. Instead, what I get back is [6, 4, 2]. They give you an example, but the example they give is clearly not what they're sending in. You will need to account for what happens when the length of the iterable is an even number as well.

Use this line for testing:

print(reverse_evens([1, 2, 3, 4, 5, 6]))

Hope this helps! :sparkles: