擅长:python、mysql、java
<p>您也可以这样编写它,它的优点是显示结构<code>[[()]*3]*3</code></p>
<pre><code>>>> P=[i[:] for i in [[()]*3]*3]
>>> P[0][0]=1
>>> P
[[1, (), ()], [(), (), ()], [(), (), ()]
</code></pre>
<p>它也比使用范围稍快。来自ipython shell:</p>
<pre><code>In [1]: timeit P = [ [()]*3 for i in range(3) ]
1000000 loops, best of 3: 1.41 us per loop
In [2]: timeit P=[i[:] for i in [[()]*3]*3]
1000000 loops, best of 3: 1.27 us per loop
</code></pre>