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

slices - reverse_evens

Hi,

writing the following in jupyter:

def reverse_evens(iterable): return iterable[-1::-2] reverse_evens('morgenbladet')

outputs: tdlngo

why don't I get this passed here?

Mer

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

def first_and_last_4(iterable):
    return iterable[:4] + iterable[-4::1]

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

def reverse_evens(iterable):
    return iterable[-1::-2]

2 Answers

Merethe Lindanger,

Keep in mind that you need to return only even indices. If there is an odd number of items [1, 2, 3, 4, 5] then your code will work; however, if there is an even number of items in the list, then your code will fail.

I solve this by getting all of the evens and then return a slice reversing that order.

def first_4(iterable):
    return iterable[:4]

def first_and_last_4(iterable):
    return first_4(iterable) + iterable[-4::1]

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

def reverse_evens(iterable):
    temp = iterable[::2]
    return temp[::-1]

I hope this helps. If you have any questions, I'd be happy to help.

It helped. Thanks a lot!