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Python Python Collections (Retired) Slices Sorting Slices

Gilang Ilhami
Gilang Ilhami
12,045 Points
Posted by Gilang Ilhami
Gilang Ilhami
12,045 Points

sorting slices

I think i got the logic wrong here The lsit ave to show every third item , bakwards, from messy_list

lists.py 
messy_list = [5, 2, 1, 3, 4, 7, 8, 0, 9, -1]

# Your code goes below here
clean_list = messy_list[:]
clean_list.sort()
silly_list = clean_list[0::3:-1]

1 Answer

Chris Howell
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Chris Howell
Python Web Development Techdegree Graduate 49,702 Points
Chris Howell
.a{fill-rule:evenodd;}techdegree seal-36
Chris Howell
Python Web Development Techdegree Graduate 49,702 Points

So first I will say be sure you read the prompt carefully on which list it is asking you to slice. It should be messy_list again not clean_list.

You can think of slicing kind of list this.

some_list[<start>:<stop>:<step>]

START - where the list will start slicing from, starting point. It will include this item. (inclusive)

STOP - the list will stop here, will not include this item in the list. (exclusive)

STEP - it hops/skips this many items, if was 2 it would skip every other item.

Examples

messy_list = [5, 2, 1, 3, 4, 7, 8, 0, 9, -1]
#            [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] index of messy_list


# -------- Example 1 ------------
# Make a new list, slicing messy_list

new_list = messy_list[0:4:1]

# --- This would read ---
# START at index 0, which is 5 in messy_list
# We will move forward 1 STEP which gets us to index 1. Which is 2 in messy_list
# We will repeat this until we hit the STOP index, which is 4. Which is 3 in messy_list
# When we hit last item, we return this sliced list.


# -------- Example 2 ------------
another_list = messy_list[::-2]

# Because we didnt pass START or STOP, It will go through the whole list.
# BUT, because we passed -2 as the STEP.
# It will go through the whole list, going backwards. 2 items at a time.
# it would return HALF the list, in backwards order.

Hope that helps?