Python范围问题

Question

我正在写一个程序，它需要确定数字的范围，就像我在user_input'a'中放置15一样，所以它应该打印范围从'a'到'b'，但不幸的是我是无法解决任何人都可以请帮助我。这是我的代码：

a = int(raw_input("How many did you say you're going to count down? ")) 
b = int(raw_input("When are you actually going to stop? ")) 
i = 0 
for i in range(a, b): 
    i = i + 1 
    print i 

，我希望它是这样工作的：

How many did you say you're going to count down? 15 
When are you actually going to stop? 8 
15 
14 
13 
12 
11 
10 
9 
8 

OR

How many did you say you're going to count down? 6 
When are you actually going to stop? 4 
6 
5 
4 

Answer 1

循环可以是：

a = int(raw_input("How many did you say you're going to count down? ")) 
b = int(raw_input("When are you actually going to stop? ")) 

for i in range(a, b-1, -1): 
    print i 

（假设计数减少）。

那你必须知道的是：

1. 的for循环为你做递减（无需i = i-1像C）。
2. range(a, b-1, -1)是从a到b-1（未包括）的列表（在Python 2中），步骤为-1。例如，您可以尝试在Python shell中执行print range(10, 5, -1)。您还可以检查range(5, 11, 2)的输出，以更好地了解range()的功能。