Learn Data Structures by Building the Merge Sort Algorithm - Step 33

Python
1

Tell us what’s happening:

Hey, so i am struggling with the last part of this questions.
i tried print("Sorted array: " + str(numbers) ) and it didn’t work, I also tried print("Sorted array: ", str(numbers)) and it also failed, so i am confused what could be the problem

Your code so far

def merge_sort(array):
    if len(array) <= 1:
        return
    
    middle_point = len(array) // 2
    left_part = array[:middle_point]
    right_part = array[middle_point:]

    merge_sort(left_part)
    merge_sort(right_part)

    left_array_index = 0
    right_array_index = 0
    sorted_index = 0

    while left_array_index < len(left_part) and right_array_index < len(right_part):
        if left_part[left_array_index] < right_part[right_array_index]:
            array[sorted_index] = left_part[left_array_index]
            left_array_index += 1
        else:
            array[sorted_index] = right_part[right_array_index]
            right_array_index += 1
        sorted_index += 1

    while left_array_index < len(left_part):
        array[sorted_index] = left_part[left_array_index]
        left_array_index += 1
        sorted_index += 1
    
    while right_array_index < len(right_part):
        array[sorted_index] = right_part[right_array_index]
        right_array_index += 1
        sorted_index += 1



# User Editable Region

 if __name__ == '__main__':
    numbers = [4, 10, 6, 14, 2, 1, 8, 5]
    print('Unsorted array: ')
    print(numbers)
    merge_sort(numbers)
    
    


# User Editable Region

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Challenge Information:

Learn Data Structures by Building the Merge Sort Algorithm - Step 33

2

Did you check the spacing?

3

Yes i did still it didn’t work, i even copied the string which is supposed to be printed, i also tried using the f-string in my print function, and i also didn’t work

4

Please share your updated code.

5 
def merge_sort(array):
    if len(array) <= 1:
        return
    
    middle_point = len(array) // 2
    left_part = array[:middle_point]
    right_part = array[middle_point:]

    merge_sort(left_part)
    merge_sort(right_part)

    left_array_index = 0
    right_array_index = 0
    sorted_index = 0

    while left_array_index < len(left_part) and right_array_index < len(right_part):
        if left_part[left_array_index] < right_part[right_array_index]:
            array[sorted_index] = left_part[left_array_index]
            left_array_index += 1
        else:
            array[sorted_index] = right_part[right_array_index]
            right_array_index += 1
        sorted_index += 1

    while left_array_index < len(left_part):
        array[sorted_index] = left_part[left_array_index]
        left_array_index += 1
        sorted_index += 1
    
    while right_array_index < len(right_part):
        array[sorted_index] = right_part[right_array_index]
        right_array_index += 1
        sorted_index += 1


 if __name__ == '__main__':
    numbers = [4, 10, 6, 14, 2, 1, 8, 5]
    print('Unsorted array: ')
    print(numbers)
    merge_sort(numbers)
    print('Sorted array: ', str(numbers))
6

I’m not sure about the indentation because the code is not properly formatted, but you need to concatenate 'Sorted array: ' and str(numbers). You are not doing it here.

7

I’ve edited your code for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

Pre-formatted-text
Pre-formatted-text1356×380 401 KB

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (').

8 
 if __name__ == '__main__':
    numbers = [4, 10, 6, 14, 2, 1, 8, 5]
    print('Unsorted array: ')
    print(numbers)
    merge_sort(numbers)
    print('Sorted array: ' + str(numbers)) # I tried this
    print('Sorted array: ', str(numbers) # I also tried this
    print(f'Sorted array: {str(numbers)}') # And this
Thank you by the way for taking your time  to assist a fellow like me, much appreciated
9

IndentationError! There’s an extra space at the beginning. Fix that and then use concatenation ( + ) to build the string.

1 Like
10

yep that was it, thank you very much

11

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