二分查找

def search(list_, key):
    """
    二分查找
    """
    low, high = 0, len(list_) - 1
    while low <= high:
        mid = (low + high) // 2
        if list_[mid] < key:
            low = mid + 1
        elif list_[mid] > key:
            high = mid - 1
        else:
            return mid


l = [i for i in range(1, 10)]
print(search(l, 5))