sorting Selection Sort (Python)


Example

Animation to show how selection sort works

enter image description here

The below example shows selection sort in Python

def sort_selection(my_list):

for pos_upper in xrange( len(my_list)-1, 0, -1):
    max_pos = 0
    for i in xrange(1, pos_upper + 1):
        if(my_list[i] > my_list[max_pos]):
            max_pos = i
            print "resetting max_pos = " + str(max_pos)

    my_list[pos_upper], my_list[max_pos] = my_list[max_pos], my_list[pos_upper]
    print "pos_upper: " + str(pos_upper) + " max_pos: " + str(max_pos) + " my_list: " + str(my_list)

return my_list


if __name__ == "__main__":

    my_list = [54,26,93,17,77,31,44,55,20]
    print "my_list: " + str(my_list)
    print sort_selection(my_list)

Output of the program:

my_list: [54, 26, 93, 17, 77, 31, 44, 55, 20]
resetting max_pos = 2
pos_upper: 8 max_pos: 2 my_list: [54, 26, 20, 17, 77, 31, 44, 55, 93]
resetting max_pos = 4
pos_upper: 7 max_pos: 4 my_list: [54, 26, 20, 17, 55, 31, 44, 77, 93]
resetting max_pos = 4
pos_upper: 6 max_pos: 4 my_list: [54, 26, 20, 17, 44, 31, 55, 77, 93]
pos_upper: 5 max_pos: 0 my_list: [31, 26, 20, 17, 44, 54, 55, 77, 93]
resetting max_pos = 4
pos_upper: 4 max_pos: 4 my_list: [31, 26, 20, 17, 44, 54, 55, 77, 93]
pos_upper: 3 max_pos: 0 my_list: [17, 26, 20, 31, 44, 54, 55, 77, 93]
resetting max_pos = 1
pos_upper: 2 max_pos: 1 my_list: [17, 20, 26, 31, 44, 54, 55, 77, 93]
resetting max_pos = 1
pos_upper: 1 max_pos: 1 my_list: [17, 20, 26, 31, 44, 54, 55, 77, 93]
[17, 20, 26, 31, 44, 54, 55, 77, 93]

Image Reference: Pirate Learner