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

Bruno Paris
Bruno Paris
3,568 Points
Posted by Bruno Paris
Bruno Paris
3,568 Points

what am i doing wrong

i don´t see the mistake here, what could it be?

slices.py 
def first_4 (whatever):
    return whatever[0:4]

def first_and_last_4 (whatever):
    s= whatever[:4]
    a = whatever[-4:]
    return s+a

def odds (whatever):
    c = list(whatever)
    return c[1::2]

def reverse_evens (whatever):
    c = list(whatever)
    return c[::-2]

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,457 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,457 Points

You are close! Currently, the code is returning every other item from the back of the list. This may or may not be the even-indexed items because it depends on the length of the collection. 

>>> reverse_evens([0, 1, 2, 3, 4, 5])
[5, 3, 1]
>>> reverse_evens([0, 1, 2, 3, 4, 5, 6])
[6, 4, 2, 0]

It's better to use a two-step approach. Get the even-indexed items, then reverse it.

Post back if you need more help. Good luck!

Bruno Paris
Bruno Paris
3,568 Points
Bruno Paris
Bruno Paris
3,568 Points

done! thank you chris