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

Posted by Joakim Vercaemst
Joakim Vercaemst
9,036 Points

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

slices.py 
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
Oscar Rojas
Oscar Rojas
4,195 Points 
def reverse_evens(thing):
    return thing[::-1][::2]
Joakim Vercaemst
Joakim Vercaemst
9,036 Points

Seems not to work

Cole Wilson
Cole Wilson
7,413 Points
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
Oscar Rojas
Oscar Rojas
4,195 Points

What exactly are you expecting from that function?

Joakim Vercaemst
Joakim Vercaemst
9,036 Points
Joakim Vercaemst
Joakim Vercaemst
9,036 Points

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!