from random import randint def num_search(first,last): mid = len(first) //2 mini = 0 maxi = len(first)  1 while first[mid] != last and mini <= maxi: if last > first[mid]: mini = mid + 1 else: maxi = mid 1 mid = (mini + maxi) // 2 if mini > maxi: return None else: return mid x = [] for i in range(15): x.append(randint(1,20)) x.sort() print(x) num = int(input("Insert any number to search the list: ")) print(num,"is found at index",num_search(x,num))

Output:
[1, 3, 4, 5, 5, 7, 7, 8, 10, 12, 14, 14, 15, 18, 20]
[4, 7, 7, 7, 7, 8, 8, 10, 11, 12, 12, 13, 13, 16, 20]
