QuickSort代码（Python）

Question

this is my first post on StackExchange, and I'm trying to figure out what's wrong with my code for a simple QuickSort program. I'm fairly sure that some integer simply needs to be adjusted by +-1 or something, so I'd like to keep the format.

The code is as follows:

def QuickSort(Array_1,lower=0,upper=-1):
    print(Array_1)
    if upper==-1:
        upper=len(Array_1)-1
    if lower<upper:
        Array_2,pivot=partition(Array_1,lower,upper)
        Array_3=QuickSort(Array_2,lower,pivot-1)
        Array_4=QuickSort(Array_3,pivot+1,upper)
        return Array_4
    else:
        return Array_1

def partition(Array,lower,upper):
    key=Array[upper]
    print(Array)
    i=lower
    j=lower-1
    z=0
    for j in range(lower,upper-1):
        print(i)
        print(j)
        if Array[j]<key:
            Array[i],Array[j]=Array[j],Array[i]
            i+=1
    Array[upper],Array[i]=Array[i],Array[upper]
    print(Array)
return (Array,i+1)

Additionally, one thing I noticed is that the code runs infinitely if I change the 'j in range(p,r-1)' to 'j in range(p,r)', but it doesn't look like it should. Thoughts?

Variables have been edited to meaningful variables. I think They were all changed correctly.

 input: [8, 18, 6, 19]
 desired output: [6,8,18,19]
 output: [19, 8, 18, 6]

 input: [16, 0, 20, 10, 5, 2]
 desired output: [0,2,5,10,16,20]
 output: [2, 0, 20, 16, 10, 5]

Answer 1

There were only small errors in your partition function as you already guessed:

1) Your for loop was not processing the last element because you used range(lower, upper-1) instead of range(lower, upper)

2) You should finally return i instead of i+1

def partition(Array,lower,upper):
    ...
    for j in range(lower,upper):
    ...
    return (Array,i)

Results:

>>> print QuickSort([8, 18, 6, 19])
[6, 8, 18, 19]    

and

>>> print QuickSort([16, 0, 20, 10, 5, 2])
[0, 2, 5, 10, 16, 20]