Python Bubble sort code

Question

I have written the below bubble sort code in Python.

def bubble_sort():
    num_list=[]
    list_cnt=input("How many numbers you would like to sort:")
    for i in range(int(list_cnt)): ### need to convert the value returned by input()
        num_list.append(input("Enter " +str(i)+" number:")) ##here we are using append method of list

    print("The values input are as follows:")
    print(num_list)

    print(len(num_list))
    ### Below new line of code added to convert list to integer###
    num_list=list(map(int,num_list))
    ## with the above line the code is now working as expected##
    max_index=len(num_list)-1 ## because list begins with 0
    print("max_index is:",max_index)
    for i in range(len(num_list)-1):
        j=0
        swapped=False
        for j in range(len(num_list)-1):
            if num_list[j] > num_list[j+1]:
                num_list[j],num_list[j+1]=num_list[j+1],num_list[j]
                print("Sorted when j=" +str(j)+ " and i=" + str(i)+ " is:\n ")
                print(num_list)
                swapped=True
        if not swapped:
            break

    print("The sorted list is :")
    print(num_list)    

bubble_sort()

Answer 1

Your code's quite good. I'd however change it in the following ways:

1. Move the creation of the lits out of the buble_sort.
2. Remove the prints from buble_sort.
3. Follow PEP8.
4. Change for i in range(...) to while True:.
5. Use better variables. num_list to array could do.
6. Use str.format, rather than string addition.
7. Change the creation of num_list to use a list comprehension.

def bubble_sort(array):
    while True:
        swapped = False
        for j in range(len(array)-1):
            if array[j] > array[j+1]:
                array[j], array[j+1] = array[j+1], array[j]
                swapped = True
        if not swapped:
            break


if __name__ == '__main__':
    amount = input("How many numbers you would like to sort:")
    array = [
        int(input("Enter {} number:".format(i)))
        for i in range(int(amount))
    ]

    print("The values input are as follows: {}".format(array))
    bubble_sort(array)
    print("The sorted list is: {}".format(array))

Answer 2

The IO code is mixed with the logic code. I separated them. Also, I made a few other changes including removing useless comments (the code should speak for itself, your comments don't add much; if you need comments, that probably means you should simplify your code). I also converted the numbers as soon as they are input.

def bubble_sort(num_list):
    for i in range(len(num_list)-1):
        swapped = False
        
        for j in range(len(num_list) - 1):
            if num_list[j] > num_list[j+1]:
                num_list[j], num_list[j+1] = num_list[j+1], num_list[j]
                swapped = True
        
        if not swapped:
            return


def main():
    num_list = []
    num_items = int(input("How many numbers you would like to sort:"))
    
    for i in range(num_items):
        num_list.append(int(input("Enter " + str(i + 1) + "st number:")))
    
    bubble_sort(num_list)
    print("The sorted list is:")
    print(num_list)

if __name__ == '__main__':
    main()