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

Dezhi Zhu
Dezhi Zhu
2,662 Points
Posted by Dezhi Zhu
Dezhi Zhu
2,662 Points

Please help

Make a function named reverse_evens that accepts a single iterable as an argument. Return every item in the iterable with an even index...in reverse. For example, with [1, 2, 3, 4, 5] as the input, the function would return [5, 3, 1]. You can do it!

slices.py 
def first_4(arg):
    return(arg[0:4])
def first_and_last_4(arg):
    return(arg[:4]+arg[-4:])
def odds(arg):
    return(arg[1::2])

def reverse_events(arg):
    return(arg[::-2])

2 Answers

Brian Anstett
Brian Anstett
5,831 Points
Brian Anstett
Brian Anstett
5,831 Points

Hey Dezhi, For what's its worth, you reverse_events() function get the wanted result of [5, 3, 1] but you named it "reverse_events()" instead of "reverse_evens()". The grader is really specific, so change the name and see if that makes it correct.

Good Luck!

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

Here's some hints:

  • you wrote "reverse_events" but the function name should be "reverse_evens"
  • a simple reverse index will only work on half of the possible cases
  • as it is now, getting "evens" or "odds" will be based on the size of the list
  • to always get evens, the index will need to be calculated based on the list size
  • another approach would be to get evens first, then reverse them in a separate operation