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Harper Frankstone
5,156 PointsGetting the last 4 items in a slice
I need to get the first 4 items, and the last 4 items in an iterable, by slicing. The function needs to return the first and last 4 items in a single variable. I think I am close but I'm not sure why it isn't working. Any help is appreciated! Thanks!
def first_4(obj):
items = obj[0:4]
return items
def first_and_last_4(obj):
first = obj[0:4]
last = obj[-4::-1]
first_last = first.extend(last)
return first_last
Harper Frankstone
5,156 PointsHey Van, so I took the step out of that last slice, but my code is still being rejected. Starting the slice at -4 should return the last four items, correct?
1 Answer
Steve Hunter
57,712 PointsHi there,
I used obj[:4] for the first four and the simply added with + the last four like obj[-4:]
That looked like:
def first_and_last_4(obj):
return obj[:4] + obj[-4:]
I hope that helps,
Steve.
Van Sanders
16,087 PointsVan Sanders
16,087 PointsKeep in mind that the brackets separate the 'start', 'stop', and 'step' like so: [start:stop;step]
So, in your last slice, you should try just defining the start so that it is 4 items from the end of the list.
Then, don't worry about the -1 step. That will make the returned value be reversed, since it will be counting from the back of the list! Just make sure your start point is -4.
Also, no need to use the extend notation. You can just return first + last.
I hope that helps!