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

Idan shami
Idan shami
13,251 Points
Posted by Idan shami
Idan shami
13,251 Points

Slice challenge, can I get an explanation?

Hi, I don't know what to do in this challenge, please give me a simple explanation and an example of what should be in the end.... though don't give me the answer, I want to try alone.... but I can't understand what I need to do...

thanks, Idan. (:

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

def first_and_last_4(iterable2):
    return iterable2[:4] + iterable2[-4:]
def odds(item):

1 Answer

Oszkár Fehér
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Oszkár Fehér
Treehouse Project Reviewer
Oszkár Fehér
.a{fill-rule:evenodd;}techdegree seal-36
Oszkár Fehér
Treehouse Project Reviewer

Hi Idan

Slicing it takes a 3 argument ["1st":"2nd":"3rd"] ---> [::] The 3rd arg it defines the step of the slice Example:

list = [0, 1, 2, 3, 4, 5, 6]
list[::1] ---> it takes the list elements one by one [0, 1, 2, 3, 4, 5, 6]
list[::2] ---> it takes every second element from the list : output ---> [0, 2, 4, 6]
list[::3] ---> [2, 5]
with negative it takes the list backwards: list[::-1] ----> [6, 5, 4, 3, 2, 1, 0]

so the 3rd arg decide the step of the elements and with minus sign the reversed items from the list decided by number of steps

list[::-3] ----> [4, 1]

I hope this helps Let me know if indeed helped you to understand

Idan shami
Idan shami
13,251 Points
Idan shami
Idan shami
13,251 Points

I completed the challenge!!!!!!! (: but I have a question, for solving the challenge I used this code:

return item[1:2544:2]

If the iterable is higher than 2544(indexes), it will show the odd indexes, but not till the end... Is there a way to set the to that he will be until the end of the iterable? any iterable... thanks ! and I hope you understand what I'm saying XD because my English isn't so good... have a fantastic day!

Idan.