FAQ: Merge Sort: Python - Finishing the Sort

This community-built FAQ covers the “Finishing the Sort” exercise from the lesson “Merge Sort: Python”.

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This exercise can be found in the following Codecademy content:

Sorting Algorithms

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While this(code below) works inside codecademy’s online ide pycharm returns an error on the : in line 6 and 7
left_sorted = [:middle_index] errors: (statement expected, found py colon) and (end of statement expected)

right_sorted =[middle_index:] errors: (statement expect, found pybracket)

I’m sure there’s a way to redefine this function but I was wondering if anyone else had this issue or if maybe I’m doing something wrong or there’s some module I would need to import to make it perform as intended. Any help welcome. I’ll keep looking for answers in the meantime. Thanks!

def merge_sort(items):

if len(items) <= 1:

return items

middle_index = len(items) // 2

left_split = items[:middle_index]

right_split = items[middle_index:]

define left_sorted and right_sorted below…

left_sorted = merge_sort(left_split)

right_sorted = merge_sort(right_split)

return merge(left_sorted, right_sorted)

def merge(left, right):

result =

while (left and right):

if left[0] < right[0]:

  result.append(left[0])

  left.pop(0)

else:

  result.append(right[0])

  right.pop(0)

if left:

result += left

if right:

result += right

return result