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

Thought this should work?

With reverse evens, the first colon is to accept the whole iterable; the second one is for even numbers only and the last one is to reverse it

def first_4(thing):
    return thing[0:4]
def first_and_last_4(thing):
    return thing[0:4] + thing[-4:]
def odds(thing):
    return thing[1::2]
def reverse_evens(thing):
    return thing[::2:-1]

4 Answers

Oscar Rojas
Oscar Rojas
4,195 Points
def reverse_evens(thing):
    return thing[::-1][::2]

Seems not to work

Cole Wilson
Cole Wilson
7,413 Points

Slices are start - step - stop.

You should be able to do thing[:-2:-1]

Oscar Rojas
Oscar Rojas
4,195 Points

What exactly are you expecting from that function?

Thanks @Cole Wilson for the reminder. I figured it out, had to separate the 2 steps and then it worked fine.

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

Thank you everyone for the help!