递归二分查找

def find(list,num):
    length = int(len(list) / 2)   #取列表长度中间值
    if length > 1:
        list_left = list[:length]
        list_right = list[length:]
        if num > list_left[-1]:
            print('num肯定在右半边的列表里')
            list = list_right
            print(list)
            return find(list,num)
        elif num < list_right[0]:
            print('num肯定在左半边的列表里')
            list = list_left
            print(list)
            return find(list,num)
    else:
        print('find it!')
find(list(range(1000)),605)