Python Bubble Sort

Here is the whole process all in the same picture:

Algorithm

1. From index 0, compare the elements with the succeeding element in the list.
2. If the element you're working on is greater than the succeeding element, swap the two elements.
3. Else, if both elements are in the correct order, then go to the next element of the succeeding element and the succeeding element and repeat step number 1.

The whole process is limited to sorting the elements into ascending order. We can do it in descending order too. The only change will be in the comparison. We check if the element we're working on is less than the next element, and if it is; we leave it and go to the next elements, while if they are not, we swap the elements. It bubbles up the smallest element. But, all the time, mostly ascending order is used and preferred.

Python Program to implement Bubble Sort

Here is the Python program to implement bubble sort on a list

def bubbleSort (list1):
n = len (list1)
 for i in range(n-1):
       for j in range(0, n-i-1):
             if list1[j] > list1 [j + 1] :
                list1 [j], list1 [j + 1] = list1 [j + 1], list1 [j]
 list1 = [7, 2, 8, 5, 4]
bubbleSort (list1)
print ("Sorted list is:")
for i in range (len (list1)):
    print ("% d" % list1 [i], end=" ")

Output:

Sorted list is:
2
4
5
7
8

Explanation:

In the above program, we wrote a function “bubbleSort” that takes the list as the parameter and in the function; we took the length of the list as the variable n. Now, we used nested loops. In the first loop, we traverse through the loop and in the second loop; we traverse through the loop till the last but one element. Now, we check if the elements are in the correct order and then swap if not.

Here is the mechanism table:

First, the list looks like [7, 2, 8, 5, 4]