Trouble implementing part of selection sort

Question

I have implemented the selection sort in python, but couldn't understand this tiny part of inner for loop.

The for loop for j, I have the range from outer index i to max length-1, this makes a lot of sense to me, but the result wouldn't count the last number in the array, and I can't think of the reason.

However, If I change the range from i to max length, it would work. (which in my knowledge should be exceeding the array since alist[len(alist)] would count 1 digit pass the max number).

#Go over the loop, find the smallest num
def swap(arr, num_1, num_2):
    temp = arr[num_1]
    arr[num_1] = arr[num_2]
    arr[num_2] = temp

def selectionSort(alist):
    for i in range(0, len(alist)-1):
        min = i
        # for j in range(i+1, len(alist)):
        # Why len(alist)-1 doesn't work?
        for j in range(i, len(alist)-1):
            if alist[j] < alist[min]:
                min = j
        if min != i :
            swap(alist,i,min)
    return alist


# Test
print "-------------Test--- ----------"
A = [2,1,9,3,4,100,99,30]
print selectionSort(A)

Answer 1

Read about ranges in Python again; you don't have a clear concept of them. range(0, 3), for example, is roughly equivalent to [0, 1, 2]. It stops just short of the second value. The same is true of slices.