( Python ) Can you swap the starting process of the selection sort?

Question

from finding the minimun and put it on the left to finding the maximum and put it on the right

def SelectionSort(a_list):
    n = len(a_list)

    for i in range(0, n-1):
        iMin = i
        print(a_list)

        for j in range(i+1, n):
            if a_list[j] < a_list[iMin]:
                iMin = j

        temp = a_list[i]
        a_list[i] = a_list[iMin]
        a_list[iMin] = temp
    
    print()
    return a_list

someList = [45,984,6,90,8946,89]
SelectionSort(someList)

Can it swap the process from minimum => maximum to minimum <= maximum

the answer should look like this.

[6, 45, 89, 89, 984, 8946]

Answer 1

Yes:

• Rename iMin to iMax
• Mirror the two ranges you use:
  • range(0, n-1) becomes range(n-1, 0, -1)
  • range(i+1, n) becomes range(i-1, -1, -1)
• Mirror the comparison operator
  • < becomes >

Result:

def SelectionSort(a_list):
    n = len(a_list)

    for i in range(n-1, 0, -1):
        iMax = i
        print(a_list)

        for j in range(i-1, -1, -1):
            if a_list[j] > a_list[iMax]:
                iMax = j

        temp = a_list[i]
        a_list[i] = a_list[iMax]
        a_list[iMax] = temp
    
    print()
    return a_list

Unrelated to your question (and as commented), swapping can be done like this:

    a_list[i], a_list[iMax] = a_list[iMax], a_list[i]