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

Prashant Gaykar
Prashant Gaykar
1,144 Points
Posted by Prashant Gaykar
Prashant Gaykar
1,144 Points

Didn't get the right values from `reverse_evens`.

I am able to obtain desire result with reverse_evens() on my machine but on treehouse it shows error.

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

def first_and_last_4(mlist):
    return mlist[0:4] + mlist[-4:]

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

def reverse_evens(mlist):
    return mlist[::-2]

1 Answer

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher
Jennifer Nordell
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there! Yes, your code works, but only in half cases. Notably, it works when the number of elements is odd. So the given the test data [1, 2, 3, 4, 5], it will return [5, 3, 1]. But if we put in [1, 2, 3, 4, 5, 6], it will return [6, 4, 2], which is not what we would expect. We would still expect to get back [5, 3, 1] as the even indexes still contain 1, 3, and 5.

You will have to do this a bit differently. First, get all the even indexes, then reverse them.

I think maybe you can get it with this hint, but let me know if you're still stuck! :sparkles:

Prashant Gaykar
Prashant Gaykar
1,144 Points
Prashant Gaykar
Prashant Gaykar
1,144 Points

ok got that! thanks Jennifer for the help.