擅长:python、mysql、java
<p>如果<code>letter</code>不是字母顺序会发生什么?确切地说,它没有被添加,因为它在<code>alpha</code>中找不到它的索引。您需要有一个<code>if/else</code>语句:</p>
<pre><code>def encode(string,keyletters):
alpha="abcdefghijklmnopqrstuvwxyz"
secret = ""
for letter in string:
if letter in alpha:
index = alpha.find(letter)
secret = secret+keyletters[index]
else:
secret = secret + letter
print secret
</code></pre>