Why my sorting code doesn't working??

Question

import random

class Sort:
def sort(self, arr):
pass

def compare(self, item1, item2):
if item1 < item2:
return 1
elif item1 > item2:
return -1
else:
return 0

def swap(self, item1, item2):
tmp = item1
item1 = item2
item2 = tmp

def isSorted(self, arr):
prev = 0
for i, j in zip(arr[:-1], arr[1:]):
now = self.compare(i, j)
if prev * now == -1:
return False
prev = now
return True

class BubbleSort(Sort):
def sort(self, arr):
n = len(arr)
for i in range(n):
for j in range(n-i-1):
if arr[j] > arr[j+1]:
self.swap(arr[j], arr[j+1])

arr=[]
for i in range(10):
arr.append(random.randint(0, 11))
print(arr)

bubblesort = BubbleSort()
bubblesort.sort(arr)
print(arr)

Answer 1

Your sort function no effect in that way, because its passing values , not by reference.. Either pass array and index values. Either use within sort function like

for i in range(n):
for j in range(n-1):
if arr[j] > arr[j+1]:
tmp = arr[j]
arr[j] = arr[j+1]
arr[j+1] = tmp

Hope it helps...

Answer 2

Isn't that python provides call-by-reference every time??

Answer 3

Not every time. There you passing values only..
Instead try
swap( arr, j, j+1) and see , also modify function defination accordingly.