<p>我运行了这段代码,得到如下错误:</p>
<pre><code>Traceback (most recent call last):
File "urllister.py", line 26, in <module>
for k in l: print k,"points to",l[k],"\n"
RuntimeError: dictionary changed size during iteration
</code></pre>
<p>我唯一要做的就是在第27行的for循环中打印</p>
^{pr2}$
<p>错误的原因是Python认为,由于您通过键访问dict,所以可以更改dict,这在这里受到限制。为了避免此错误,您可以使用<code>get</code>方法,然后您的语句将如下所示:</p>
<pre><code>for k in l:
print k,"points to",l.get(k),"\n"
</code></pre>