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

Posted by Kunal Berry
Kunal Berry
769 Points

Make a function named reverse_evens that can perform [1,2,3,4,5] into [5,3,1]

Not able to solve. Please Help!

slices.py 
def first_4(item):
    return item[0:4]
def first_and_last_4(item):
    abc = item[0:4]
    abc1 = item[-4:]
    return abc + abc1
def odds(item):
    return item[1::2]
def reverse_evens(item):
    return item[-1::2]

1 Answer

Jinjia Lin
Jinjia Lin
11,942 Points
Jinjia Lin
Jinjia Lin
11,942 Points

Hi,

There are no major problems with your code, except for the very last index slicer.

item[-1::2] will begin slicing from the last element, and then move 2 steps forward.

However, that also means only the last element will be returned, since moving 2 steps forward from the last element does not give us any other element.

Now, what we want to do is to move backwards, instead of forwards.

Why don't you try it yourself? ;)

I shall not reveal the answer yet, for the sake of your learning.