my_search.py

import random

alist = []
for i in range(1, 101):
    alist.append(i)
num = random.choice(alist)
# 请完善二分查找函数binary_search(),查找出num在列表alist里面的索引位置

def binary_search(alist,num):
    low=0
    high=len(alist)-1
    while low<=high:
        mid=(low+high)//2
        guess=alist[mid]
        if guess==num:
            return mid
        elif guess<num:
            low=mid+1
        else:
            high=mid-1
    return None

result = binary_search(alist,num)
print("老师给的数字是",num)
print("他的索引在",result)