擅长:python、mysql、java
<p><code>index()</code><a href="https://docs.python.org/3.4/tutorial/datastructures.html" rel="nofollow">actually returns the index of the value that you pass to the method</a>。出现错误是因为值<code>4</code>不在调用<code>index()</code>方法的列表中。如果在从用户处获取提示后,已经将其转换为<code>int()</code>,那么您只需从列表中指定该索引处的元素,如下所示:</p>
<pre><code>s1pick = set1[side1]
s2pick = set2[side2]
</code></pre>
<p>不过,要小心。您得到的<code>input()</code>可能超出了列表的范围。因此,我会将您的输入放入while循环,以确保您得到有效的输入:</p>
<pre><code>side1 = # input code
side2 = # input code
while side1 not in range(len(set1)) or side2 not in range(len(set2)):
side1 = # input code
side2 = # input code
</code></pre>