擅长:python、mysql、java
<p>Lambda只在<code>map</code>调用时创建一次</p>
<pre><code>In [20]: l = list(range(100000))
In [21]: %timeit list(map(lambda x: x * 2, l))
100 loops, best of 3: 13.8 ms per loop
In [22]: g = lambda x: x * 2
In [23]: %timeit list(map(g, l))
100 loops, best of 3: 13.8 ms per loop
</code></pre>
<p>如您所见,执行时间没有改变。</p>