擅长:python、mysql、java
<p>您正在将相同的列表<code>to_add</code>添加到<code>lst</code>:</p>
<pre><code>>>> a = [None]
>>> b = [a]
>>> c = [a]
>>> print a, b, c
[None] [[None]] [[None]]
>>> a[0] = 1
>>> print a, b, c
[1] [[1]] [[1]]
</code></pre>