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

Posted by Travis Vance
Travis Vance
2,989 Points

Reverse Evens Challange

This code works as expected in console, with example list and others (i.e. returns only even numbers in reverse order. However, it fails in the slices.py test. Can someone point out what I'm missing? Thanks!

slices.py 
def first_4(items):
    items_list = list(items)
    thing = items_list[0:4]
    return thing

def first_and_last_4(items):
    items_list = list(items)
    thing1 = items_list[0:4]
    thing2 = items_list[-4:]
    thing3 = thing1 + thing2
    return thing3

def odds(items):
    items_list = list(items)
    thing = items_list[1::2]
    return thing

def reverse_evens(item):
    item_list = list(item)
    reverse_list = item_list[::-1]
    evens = reverse_list[1::2]
    return evens

2 Answers

Steven Parker
Steven Parker
229,732 Points
Steven Parker
Steven Parker
229,732 Points

This code will work in half of the possible cases, depending on the length of the list. You probably tested it with "lucky data".

But you can make it work in all cases by extracting the even indexed items first, and then reversing them.

Travis Vance
Travis Vance
2,989 Points
Travis Vance
Travis Vance
2,989 Points

Thanks, Steven! :thumbsup:

Steven Parker
Steven Parker
229,732 Points
Steven Parker
Steven Parker
229,732 Points

Travis Vance — Glad to help. You can mark a question solved by choosing a "best answer".
Happy coding!