Classic sorting algorithm for sorting items.

Written in Python, this is my take on the algorithm, it looks a bit different than other examples. Most likely, this is due to my desire to abort processing as early as I can with the “vars for optimization”…

def bubble_sort(arr):
    # BigO == n^2


    # 0 Elements: Exception
    if len(arr) == 0:
        raise Exception('No Elements')

    # 1 Element: Early Return
    if len(arr) == 1:
        return arr

    # vars for optimization
    numItems = len(arr)
    numPasses = 1
    sortMade = True

    # perform until no swaps made
    while sortMade:

        sortMade = False

        maxChecks = numItems-numPasses
        for x in range(maxChecks):

            if arr[x] > arr[x+1]:
                val = arr[x]
                arr[x] = arr[x+1]
                arr[x+1] = val
                sortMade = True

        numPasses += 1


    return arr

TESTS! Anytime the function has simple ins/outs and a well defined use, there’s no excuse to not have tests.

import pytest
import random
from bubble_sort import bubble_sort


def test_func_exists():
    bubble_sort([1])


def test_sort():
    input = [1,5,3,2,4]
    actual = bubble_sort(input)
    expected = [1,2,3,4,5]
    assert actual == expected

def test_all_same():
    input = [3,3,3,3,3,3,3]
    actual = bubble_sort(input)
    expected = [3,3,3,3,3,3,3]
    assert actual == expected

def test_sort_zero():
    with pytest.raises(Exception):
         bubble_sort([])

def test_sort_lots():
    input = []
    for x in range(1000):
        input.append(random.randint(1,1000))

    actual = bubble_sort(input)
    expected = input
    expected.sort()

    assert actual == expected