擅长:python、mysql、java
<p>函数<code>range(x)</code>生成<code>[0,1,2,3,4]</code>的列表。在<code>for</code>循环中,您迭代该列表。在</p>
<p>您的代码相当于:</p>
<pre><code>for j in [0,1,2,3]:
for i in [0,1,2,3]:
print i
for i in [0,1]:
print i
for i in [0,1]:
print i
for i in [0,1]:
print i
</code></pre>