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()