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

Posted by Lerena Holloway
Lerena Holloway
9,855 Points

Reversing a list using negative integers

I was finishing up the challenge on lists. It was to print out the list in reverse order, but every other index. I wrote this code and it didn't work. But when I copied it and pasted it into my Spider text editor, it gave back the example they used; it worked. I'm not sure why it's not working in the challenge editor.

Here's my code:

def reverse_evens(some_list): reverse_list = some_list[::-1] return reverse_list[::2]

Thanks for your help!

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

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

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

def reverse_evens(some_list):
    reverse_list = some_list[::-1]
    return reverse_list[::2]

1 Answer

Steven Parker
Steven Parker
231,007 Points
Steven Parker
Steven Parker
231,007 Points

With the current code, whether you get "reverse evens" or "reverse odds" will depend on the length of the list.

Try slicing the even indexes first, and then reversing that list.

Lerena Holloway
Lerena Holloway
9,855 Points

That worked! Thanks