Python/Merge Sort/Call by Reference中的递归

Question

很抱歉，我是StackOverFlow&蟒蛇我已经为Merge_Sort编写了一段代码，但它没有运行，因为数组的值在从递归调用返回时会丢失
编码环境：Python3.x
OS:Linux(Ubuntu 18.04(
下面是我的代码：

class sort: 
def __init__(self, arr, n):
self.arr = arr
self.n = n   
def __init__(self, arr, m, n):
self.arr = arr
self.m = m
self.n = n
arrS = arr.copy()
arrL = [0] * (n - int((m + n)/2) + 1)
arrR = [0] * (n - (m + 1))
def Merge_sort(self,arr,first,last):
mid = int((first + last) / 2)
arrMain = arr[first:last+1]
arrLeft = arr[first:mid+1]
arrRight = arr[mid+1:last+1]
arrL = [0] * (mid - first + 1)
arrR = [0] * (last - mid + 1)
arrN = [0] * ( last - first + 1)
if first < last:
#Sort Left Array
self.Merge_sort(arr, first, mid)
#Sort Right Array
self.Merge_sort(arr, mid+1, last)
#I defined the below 3 variables while debugging to view the list
arrL = arr[first:mid+1]
arrR = arr[mid+1:last+1]
print("Left Array: " + str(arrL))
print("Right Array: " + str(arrR))
x = len(arrL)
y = len(arrR)
i = j = k = 0
while i < x and j < y:
if (arrL[i] <= arrR[j]):
arrN[k] = arrL[i]
i += 1
else:
arrN[k] = arrR[j]
j += 1
# end-if#001
k += 1
while (i < x):
arrN[k] = arrL[i]
i += 1
k += 1
while (j < y):
arrN[k] = arrR[j]
j += 1
k += 1
arr = arrN.copy()
print("Merged Array:" + str(arr))
return arrN
#End-if#001
from Sort import sort
arr = [7, 5, 4 ,9, 3, 2 , 0, 1, 6, 8]
n = 0
sort4 = sort(arr, 0, int(len(arr)))
sort4.arr = arr.copy()
sort4.Merge_sort(sort4.arr, 0, int(len(arr)) - 1) 

程序的输入：arr=[7，5，4，9，3，2，0，1，6，8]
程序的输出：左数组：[7，5,4，9，3]右数组：[2，0,1,6,8]
合并数组：[2,0,1,6,7,5,4,8,9,3]
在程序结束时，它似乎只是合并了我的原始数组
请提出建议。

Answer 1

只是通知您，问题已经解决。我没有正确返回值。下面是我的代码，仅供参考。

def Merge_sort(self,arr,first,last):
mid = int((first + last) / 2)
arrMain = arr[first:last+1]
arrLeft = arr[first:mid+1]
arrRight = arr[mid+1:last+1]
arrL = [0] * (mid - first + 1)
arrR = [0] * (last - mid + 1)
arrN = [0] * ( last - first + 1)
if first < last:
#Sort Left Array
arrL = self.Merge_sort(arr, first, mid)
#Sort Right Array
arrR = self.Merge_sort(arr, mid+1, last)
#arrL = arr[first:mid+1]
#arrR = arr[mid+1:last+1]
print("Left Array: " + str(arrL))
print("Right Array: " + str(arrR))
x = int(len(arrL))
y = int(len(arrR))
i = j = k = 0
while i < x and j < y:
if (arrL[i] <= arrR[j]):
arrN[k] = arrL[i]
i += 1
else:
arrN[k] = arrR[j]
j += 1
# end-if#001
k += 1
while (i < x):
arrN[k] = arrL[i]
i += 1
k += 1
while (j < y):
arrN[k] = arrR[j]
j += 1
k += 1
arr = arrN.copy()
print("Merged Array:" + str(arr))
return arrN
#End-if#001
return arrMain