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

What am I doing wrong...reverse_evens?

When I run the reverse_evens function in a workspace I get the right values returned, however when I run it in the code challenge it tells me I did not get the right values.

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

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

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

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

Don't worry all - I've done it :)

2 Answers

unknown member
PLUS
unknown member
Courses Plus Student 18,937 Points

You need to check whether your "item" has even or odd number of elements. Write small "if" statement to check that and only afterwards you will know whether your last element in "item" is odd or even.

Tom Finch
Tom Finch
1,175 Points

Not sure how to post my code correctly here so it may come through incorrect. But this is what I did.

  def reverse_evens(item):
      evenIndex = item[::2]
      evenReverse = evenIndex[::-1]
      return(evenReverse)

I basically made a list from index 0 and skipped in 2's. This way I know the index will be all evens no matter what. I then reversed the list.

Nicely done Tom. Did not think of it.

Great solution!