I created the class Sorter which sets the variable self.list in the __init__ equal to a given argument. I then created a function selectionSort which should copy the value of self.list into a new variable unsortedList. That worked out, but when I then change unsortedList, the self.list variable changes as well. Here's my code:
class Sorter:
def __init__(self, list):
self.list = list
def selectionSort(self):
unsortedList = self.list
sortedList = []
indexSmallest = 0
while len(unsortedList)>0:
for i in range(len(unsortedList)):
if unsortedList[i] <= unsortedList[indexSmallest]:
indexSmallest = i
sortedList.append(unsortedList[indexSmallest])
unsortedList.pop(indexSmallest)
indexSmallest = 0
return sortedList
sorter = Sorter([2,6,1,8,5])
print(sorter.selectionSort())
I expect self.list to be the same as before calling the selectionSort() function but the result I get is an empty self.list variable.
Use either:
#1
unsortedList = self.list.copy()
Or
#2
unsortedList = self.list[:]
Or
#3
import copy
unsortedList = copy.deepcopy(self.list)
Explanation:
When you do an assignment via =, it really is referring to the same list just that now that list has 2 different names.
To circumvent this, use #1 or #2 methods -> you would require the .copy() inbuilt function or using [:].
As for #3, this is used when shallow copying isn't enough because you might have mutable objects within the list itself.
For a greater understanding on copy vs deepcopy, visit and read here
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