python 二分查找

# coding=utf-8
# python 二分查找
def fn(list1, number):
    low = 0
    high = len(list1) - 1
    while low <= high:
        mid = (low + high) / 2
        guess = list1[mid]
        if guess == number:
            return mid
        elif guess > number:
            high = mid - 1
        else:
            low = mid + 1
    return None


my_list = [1, 3, 5, 7, 9, 11, 15]
print (fn(my_list, 15))