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

tyler bucasas
tyler bucasas
2,453 Points
Posted by tyler bucasas
tyler bucasas
2,453 Points

slices.py

when I put the reverse_evens in the python shell it returns the right numbers, but when I check the question is says its not receiving the right numbers. someone please help

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

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

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

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

1 Answer

Kia Matthews
Kia Matthews
3,402 Points
Kia Matthews
Kia Matthews
3,402 Points

What I did was to first, create a new variable which is a list of all the even numbers. Then I returned that list in reverse. There may be a way to do this all on one line, however. But this worked for me.

def reverse_evens(list):
    list_v2 = list[0::2]
    return(list_v2[::-1])

Actually, I just tried it out on one line:

def reverse_evens(list):
    return(list[0::2][::-1])

So I'm doing the exact same thing - getting a list of evens and then reversing that list.

In your code, you were only reversing the list by an increment of 2. That would only work if the list of numbers were odd (that is, the last index was an even number).