unsorted_list = [20, 7, 3, 4, 12, 15, 2, 1]

Selection Sort

Pseudocode

for j ← 1 to n-1

smallest ← j

for i ← j + 1 to n

if A[ i ] < A[ smallest ]

smallest ← i

Exchange A[ j ] ↔ A[ smallest ]

def selection_sort(a):
for j in range(len(a) - 1):
minimum = j # assume that element with j index is minimum
for i in range(
j + 1, len(a)
): # compare it with unsorted elements(we leave the sorted elements behind)
if a[i] < a[minimum]:
minimum = i # update minimum index with the smaller element
a[j], a[minimum] = (
a[minimum],
a[j],
) # swap the elements that are assumed minimum and actual minimum found in unsorted list
print("after selection sort:")
print(a)

selection_sort(unsorted_list)